Imaging lens, optical apparatus and method for forming image using this imaging lens

ABSTRACT

An imaging lens includes a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power, which are disposed in order from an object. The first lens group has a first lens component having a negative refractive power and a second lens component having a positive refractive power, which are disposed in order from the object, and conditions expressed by the expressions 0.12&lt;f/f 1 &lt;0.47 and 0.016&lt;D 12 /f&lt;0.079 are satisfied, when f 1  is a focal length of the first lens group, f is a focal length of the imaging lens, and D 12  is an air distance between the first lens component and the second lens component of the first lens group.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a division of application Ser. No. 12/421,323 filedApr. 9, 2009 now U.S. Pat. No. 7,940,478. Also, this application claimsthe benefit of U.S. Provisional Application Nos. 61/044,235, 61/044,258,61/044,375 and 61/044,387 filed Apr. 11, 2008. This application alsoclaims the priority of Japanese Patent Applications No. 2008-103746,2008-103747, 2008-103748 and 2008-103749 which is hereby incorporated byreference.

FIELD OF THE INVENTION

The present invention relates to an imaging lens which is suitable for aphotographic camera and video camera, an optical apparatus, and a methodfor forming an image of an object using this imaging lens.

BACKGROUND OF THE INVENTION

As a compact lens used for a photograph camera and video camera, havingabout a 50° angle of view, and a relatively bright F number, an imaginglens having a first lens group comprised of a negative lens and apositive lens, and a second lens group comprised of a stop, a cementedlens of a negative lens and a positive lens, and a positive lens, havebeen available (e.g. Japanese Patent Application Laid-Open No.H9-189856).

On the other hand, along with the recent demand for smaller, slimmer andlighter cameras, holding a camera during actual use is becomingdifficult, and shooting errors due to blur caused by a motion of thecamera are increasing. A slight blur of a camera generated duringshooting (e.g. blur of a camera generated when the user presses arelease button) causes an image blur during exposure, and deterioratesthe image quality.

To solve this problem, a known method for correcting an image blur iscombining a detection system for detecting the blur caused by motion ofa camera, a computing system to control a shift lens group according toa value which is output from the detection system, and a drive systemfor shifting the shift lens group, as an optical system which can shiftan image of the imaging lens, and driving the shift lens group so as tocompensate for the image blur caused by the motion of a camera.

SUMMARY OF THE INVENTION

In a conventional lens, however, if focusing is performed using theimaging lens, the total length of the lens becomes long when focus isadjusted on a close object. Another problem is that the correction ofvarious aberrations during close up shooting is insufficient.

Also in the case of a conventional camera, it is difficult to implementboth good correction of various aberrations and suppression ofperformance change during lens shift when an image blur is corrected.

It is an object of the present invention to provide a compact imaginglens which can correct various aberrations satisfactorily from infinityto a close object, and can implement high performance on an entirescreen, and an optical apparatus and a method for forming an image of anobject using this imaging lens.

It is another object of the present invention to provide a compactimaging lens which can correct various aberrations satisfactorily, andcan minimize performance change during lens shift, and can implementhigh optical performance on an entire screen, and an optical apparatusand a method for forming an image of an object using this imaging lens.

Means to Solve the Problems

An imaging lens according to a first aspect of the present inventioncomprises an object side lens group having a positive refractive power,an aperture stop, and an image side lens group having a positiverefractive power which are disposed in order from an object, wherein theobject side lens group comprises a first lens component having anegative refractive power and a second lens component having a positiverefractive power, which are disposed in order from the object, andconditions expressed by the following expressions 0.12<f/f1<0.47 and0.016<D12/f<0.079 are satisfied, where f1 is a focal length of theobject side lens group, f is a focal length of the imaging lens, and D12is an air distance between the first lens component and the second lenscomponent of the object side lens group.

It is preferable that the object side lens group comprises the firstlens component made of a negative meniscus lens having a convex surfacefacing the object, and the second lens component made of a positivemeniscus lens having a convex surface facing the object, which aredisposed in order from the object.

It is also preferable that a condition expressed by the followingexpression nd1>1.65 is satisfied, where nd1 is a refractive index of thefirst lens component of the object side lens group on the d-line.

It is also preferable that a condition expressed by the followingexpression 3.8<(r2F+r1R)/(r2F−r1R)<11.8 is satisfied, where r1R is aradius of curvature of an image side lens surface of the first lenscomponent, and r2F is a radius of curvature of an object side lenssurface of the second lens component.

It is also preferable that the image side lens group comprises abiconvex positive lens, and the biconvex positive lens includes at leastone aspherical surface.

An imaging lens according to a second aspect of the present inventioncomprises an object side lens group having a positive refractive power,an aperture stop, and an image side lens group having a positiverefractive power, which are disposed in order from an object, whereinthe object side lens group further comprises a plurality of lenses, theimage side lens group further comprises a cemented lens of a negativelens component having a concave surface facing the object and a positivelens component having a convex surface facing the image, and a biconvexpositive lens component, which are disposed in order from the object,and a condition expressed by the following expression 3.0<TL/Ymax<4.0 issatisfied, where TL is a total length of the imaging lens, and Ymax is amaximum image height.

It is preferable that a condition expressed by the following expression1.7<TL/Σd<2.2 is satisfied, where TL is a total length of the imaginglens, and Σd is a length on the optical axis, from a lens surfaceclosest to the object in the object side lens group to a lens surfaceclosest to the image in the image side lens group.

It is also preferable that the image side lens group comprises acemented lens of a negative meniscus lens having a concave surfacefacing the object and a positive meniscus lens having a convex surfacefacing the image, and a biconvex positive lens, which are disposed inorder from the object.

An Imaging lens according to a third aspect of the present inventioncomprises an object side lens group having a positive refractive powerand an image side lens group having a positive refractive power with anair distance from the object side lens group, which are disposed inorder from the object, wherein the image side lens group furthercomprises a cemented lens of a negative lens component having a concavesurface facing the object and a positive lens component having a convexsurface facing the image, and a biconvex positive lens component, whichare disposed in order from the object, and all or a part of the imageside lens group can be shifted in a direction substantiallyperpendicular to the optical axis as a shift lens group.

It is preferable that a condition expressed by the following expression0.80<f/fS<1.10 is satisfied, where f is a focal length of the imaginglens, and fS is a focal length of the shift lens group.

It is also preferable that a condition expressed by the followingexpression 0.13<f2/f1<0.47 is satisfied, where f1 is a focal length ofthe object side lens group, and f2 is a focal length of the image sidelens group.

It is also preferable that an aperture stop is disposed between theobject side lens group and the image side lens group.

It is also preferable that the focus on a close object is adjusted bymoving the image side lens group toward the object.

An imaging lens according to a fourth aspect of the present inventioncomprises an object side lens group having a positive refractive power,an aperture stop, and an image side lens group having a positiverefractive power which are disposed in order from an object, wherein theobject side lens group comprises a negative lens component and apositive lens component, which are disposed in order from the object,the image side lens group comprises a cemented lens of a negative lenscomponent and a first positive lens component, and a second positivelens component, which are disposed in order from the object, andconditions expressed by the following expressions nd5<1.67 and νd5>50.0are satisfied, where nd5 is a refractive index of the second positivelens component of the image side lens group on the d-line, and νd5 is anAbbe number of the second positive lens component of the image side lensgroup on the d-line.

It is preferable that a condition expressed by the following expression−0.30<(r5R+r5F)/(r5R−r5F)<0.40 is satisfied, where r5F is a radius ofcurvature of an object side lens surface of the second positive lenscomponent of the image side lens group, and r5R is a radius of curvatureof an image side lens surface of the second positive lens component ofthe image side lens group.

It is preferable that a condition expressed by the following expression0.60<f/f5<0.90 is satisfied, where f is a focal length of the imaginglens, and f5 is a focal length of the second positive lens component ofthe image side lens group.

It is also preferable that the negative lens component of the objectside lens group includes at least one aspherical surface.

It is also preferable that the image side lens group includes at leastone aspherical surface.

An optical apparatus according to the present invention comprises animaging lens that forms an image of an object on a predetermined imagesurface, wherein the imaging lens is the above mentioned imaging lens.

A method for manufacturing an imaging lens according to a first aspectof the present invention, comprises the steps of: assembling an objectside lens group having a positive refractive power, an aperture stop,and an image side lens group having a positive refractive power in alens barrel in order from an object; configuring the object side lensgroup by disposing a first lens component having a negative refractivepower and a second lens component having a positive refractive power inorder from the object when the step of assembling is performed, whereina condition expressed by the following expressions 0.12<f/f1<0.47 and0.016<D12/f<0.079 are satisfied, where f1 is a focal length of theobject side lens group, f is a focal length of an imaging lens, and D12is an air distance between the first lens component and the second lenscomponent of the object side lens group.

In this case, it is preferable that the object side lens group comprisesthe first lens component made of a negative meniscus lens having aconvex surface facing the object, and the second lens component made ofa positive meniscus lens having a convex surface facing the object,which are disposed in order from the object.

It is also preferable that a condition expressed by the followingexpression nd1>1.65 is satisfied, where nd1 is a refractive index of thefirst lens component of the object side lens group on the d-line.

It is also preferable that a condition expressed by the followingexpression 3.8<(r2F+r1R)/(r2F−r1R)<11.8 is satisfied, where r1R is aradius of curvature of an image side lens surface of the first lenscomponent, and r2F is a radius of curvature of an object side lenssurface of the second lens component.

It is also preferable that the image side lens group comprises abiconvex positive lens, and the biconvex positive lens includes at leastone aspherical surface.

A method for manufacturing an imaging lens according to a second aspectof the present invention, comprises the steps of: assembling an objectside lens group having a positive refractive power, an aperture stop,and an image side lens group having a positive refractive power, in alens barrel in order from an object; configuring the object side lensgroup by disposing a plurality of lenses when the step of assembling isperformed; and configuring the image side lens group by disposing acemented lens of a negative lens component having a concave surfacefacing the object and a positive lens component having a convex surfacefacing the image, and a biconvex positive lens component, in order fromthe object when the step of assembling is performed, wherein a conditionexpressed by the following expression 3.0<TL/Ymax<4.0 is satisfied,where TL is a total length of the imaging lens, and Ymax is a maximumimage height.

In this manufacturing method, it is preferable that a conditionexpressed by following expression 1.7<TL/Σd<2.2 is satisfied, where TLis a total length on the optical axis, from the imaging lens, and Σd isa length of a lens surface closest to the object in the object side lensgroup to a lens surface closest to the image in the image side lensgroup.

It is also preferable that the image side lens group further comprises acemented lens of a negative meniscus lens having a concave surfacefacing the object and a positive meniscus lens having a convex surfacefacing the image, and a biconvex positive lens, which are disposed inorder from the object.

A method for manufacturing an imaging lens according to a third aspectof the present invention, comprises the steps of: assembling an objectside lens group having a positive refractive power and an image sidelens group having a positive refractive power with an air distance fromthe object side lens group in a lens barrel in order from the objectside; configuring the image side lens group by disposing a cemented lensof a negative lens component having a concave surface facing the objectand a positive lens component having a convex surface facing the image,and a biconvex positive lens component in order from the object when thestep of assembling is performed; and assembling all or a part of theimage side lens group as a shift lens group to be shifted in a directionsubstantially perpendicular to the optical axis is possible.

In this manufacturing method, it is preferable that a conditionexpressed by the following expression 0.80<f/fS<1.10 is satisfied, wheref is a focal length of the imaging lens, and fS is a focal length of theshift lens group.

It is also preferable that a condition expressed by the followingexpression 0.13<f2/f1<0.47 is satisfied, where f1 is a focal length ofthe object side lens group, and f2 is a focal length of the image sidelens group.

It is also preferable that an aperture stop is disposed between theobject side lens group and the image side lens group.

It is also preferable that the focus on a close object is adjusted bymoving the image side lens group toward the object.

A method for manufacturing an imaging lens according to a fourth aspectof the present invention, comprises the steps of: assembling an objectside lens group having a positive refractive power, an aperture stop,and an image side lens group having a positive refractive power in alens barrel in order from the object; configuring the object side lensgroup by disposing a negative lens component and a positive lenscomponent in order from the object when the step of assembling isperformed; and configuring the image side lens group by disposing acemented lens of a negative lens component and a first positive lenscomponent, and a second positive lens component in order from the objectwhen the step of assembling is performed, wherein conditions expressedby the following expressions nd5<1.67 and νd5>50.0 are satisfied, wherend5 is a refractive index of the second positive lens component of theimage side lens group on the d-line, and νd5 is an Abbe number of thesecond positive lens component of the image side lens group on thed-line.

In this method, it is preferable that a condition expressed by thefollowing expression −0.30<(r5R+r5F)/(r5R−r5F)<0.40 is satisfied, wherer5F is a radius of curvature of an object side lens surface of thesecond positive lens component of the image side lens group, and r5R isa radius of curvature of an image side lens surface of the secondpositive lens component of the image side lens group.

It is also preferable that a condition expressed by following expression0.60<f/f5<0.90 is satisfied, where f is a focal length of the imaginglens, and f5 is a focal length of the second positive lens component ofthe image side lens group.

It is also preferable that the negative lens component of the objectside lens group includes at least one aspherical surface.

It is also preferable that the image side lens group includes at leastone aspherical surface.

Advantageous Effects of the Invention

According to the present invention, an imaging lens of which angle ofview exceeds 60°, and F number is about 2.8, and which can correctvarious aberrations well from infinity to a close object, is compact,and can implement high optical performance on an entire screen, anoptical apparatus and a method for forming an image of an object usingthis imaging lens, can be provided.

Also according to the present invention, an imaging lens which cancorrect various aberrations satisfactorily, minimizes performance changeduring a lens shift, is compact, and has high optical performance on anentire screen, and an optical apparatus and a method for forming animage of an object using this imaging lens, can be provided.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given herein below and the accompanying drawingswhich are given by way of illustration only and thus are not limitativeof the present invention.

FIGS. 1A and 1B show a digital still camera having an imaging lensaccording to the first embodiment, where 1A is a front view and 1B is arear view;

FIG. 2 is a cross-sectional view along the A-A′ line in FIG. 1A;

FIG. 3 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-1;

FIGS. 4A and 4B are graphs showing various aberrations of Example 1-1,where 4A are graphs showing various aberrations upon focusing oninfinity, and 4B are graphs showing various aberrations upon focusing ona close object;

FIG. 5 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-2;

FIGS. 6A and 6B are graphs showing various aberrations of Example 1-2,where 6A are graphs showing various aberrations upon focusing oninfinity, and 6B are graphs showing various aberrations upon focusing ona close object;

FIG. 7 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-3;

FIGS. 8A and 8B are graphs showing various aberrations of Example 1-3,where 8A are graphs showing various aberrations upon focusing oninfinity, and 8B are graphs showing various aberrations upon focusing ona close object;

FIG. 9 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-4;

FIGS. 10A and 10B are graphs showing various aberrations of Example 1-4,where 10A are graphs showing various aberrations upon focusing oninfinity, and 10B are graphs showing various aberrations upon focusingon a close object;

FIG. 11 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-5;

FIGS. 12A and 12B are graphs showing various aberrations of Example 1-5,where 12A are graphs showing various aberrations upon focusing oninfinity, and 12B are graphs showing various aberrations upon focusingon a close object;

FIG. 13 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-6;

FIGS. 14A and 14B are graphs showing various aberrations of Example 1-6,where 14A are graphs showing various aberrations upon focusing oninfinity, and 14B are graphs showing various aberrations upon focusingon a close object;

FIG. 15 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-7;

FIGS. 16A and 16B are graphs showing various aberrations of Example 1-7,where 16A are graphs showing various aberrations upon focusing oninfinity, and 16B are graphs showing various aberrations upon focusingon a close object;

FIG. 17 is a cross-sectional view depicting a configuration of theimaging lens according to Example 1-8;

FIGS. 18A and 18B are graphs showing various aberrations of Example 1-8,where 18A are graphs showing various aberrations upon focusing oninfinity, and 18B are graphs showing various aberrations upon focusingon a close object;

FIG. 19 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-1;

FIGS. 20A and 20B are graphs showing various aberrations of Example 2-1,where 20A are graphs showing various aberrations upon focusing oninfinity, and 20B are graphs showing various aberrations upon focusingon a close object;

FIG. 21 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-2;

FIGS. 22A and 22B are graphs showing various aberrations of Example 2-2,where 22A are graphs showing various aberrations upon focusing oninfinity, and 22B are graphs showing various aberrations upon focusingon a close object;

FIG. 23 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-3;

FIGS. 24A and 24B are graphs showing various aberrations of Example 2-3,where 24A are graphs showing various aberrations upon focusing oninfinity, and 24B are graphs showing various aberrations upon focusingon a close object;

FIG. 25 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-4;

FIGS. 26A and 26B are graphs showing various aberrations of Example 2-4,where 26A are graphs showing various aberrations upon focusing oninfinity, and 26B are graphs showing various aberrations upon focusingon a close object;

FIG. 27 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-5;

FIGS. 28A and 28B are graphs showing various aberrations of Example 2-5,where 38A are graphs showing various aberrations upon focusing oninfinity, and 28B are graphs showing various aberrations upon focusingon a close object;

FIG. 29 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-6;

FIGS. 30A and 30B are graphs showing various aberrations of Example 2-6,where 30A are graphs showing various aberrations upon focusing oninfinity, and 30B are graphs showing various aberrations upon focusingon a close object;

FIG. 31 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-7;

FIGS. 32A and 32B are graphs showing various aberrations of Example 2-7,where 32A are graphs showing various aberrations upon focusing oninfinity, and 32B are graphs showing various aberrations upon focusingon a close object;

FIG. 33 is a cross-sectional view depicting a configuration of theimaging lens according to Example 2-8;

FIGS. 34A and 34B are graphs showing various aberrations of Example 2-8,where 34A are graphs showing various aberrations upon focusing oninfinity, and 34B are graphs showing various aberrations upon focusingon a close object;

FIG. 35 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-1;

FIGS. 36A and 36B are graphs showing various aberrations of Example 3-1,where 36A are graphs showing various aberrations upon focusing oninfinity, and 36B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 37 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-2;

FIGS. 38A and 38B are graphs showing various aberrations of Example 3-2,where 38A are graphs showing various aberrations upon focusing oninfinity, and 38B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 39 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-3;

FIGS. 40A and 40B are graphs showing various aberrations of Example 3-3,where 40A are graphs showing various aberrations upon focusing oninfinity, and 40B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 41 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-4;

FIGS. 42A and 42B are graphs showing various aberrations of Example 3-4,where 42A are graphs showing various aberrations upon focusing oninfinity, and 42B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 43 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-5;

FIGS. 44A and 44B are graphs showing various aberrations of Example 3-5,where 44A are graphs showing various aberrations upon focusing oninfinity, and 44B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 45 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-6;

FIGS. 46A and 46B are graphs showing various aberrations of Example 3-6,where 46A are graphs showing various aberrations upon focusing oninfinity, and 44B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 47 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-7;

FIGS. 48A and 48B are graphs showing various aberrations of Example 3-7,where 48A are graphs showing various aberrations upon focusing oninfinity, and 48B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 49 is a cross-sectional view depicting a configuration of theimaging lens according to Example 3-8;

FIGS. 50A and 50B are graphs showing various aberrations of Example 3-8,where 50A are graphs showing various aberrations upon focusing oninfinity, and 50B are graphs showing coma aberrations during a lensshift (0.1 mm);

FIG. 51 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-1;

FIGS. 52A and 52B are graphs showing various aberrations of Example 4-1,where 52A are graphs showing various aberrations upon focusing oninfinity, and 52B are graphs showing various aberrations upon focusingon a close object;

FIG. 53 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-2;

FIGS. 54A and 54B are graphs showing various aberrations of Example 4-2,where 54A) are graphs showing various aberrations upon focusing oninfinity, and 54B are graphs showing various aberrations upon focusingon a close object;

FIG. 55 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-3;

FIGS. 56A and 56B are graphs showing various aberrations of Example 4-3,where 56A are graphs showing various aberrations upon focusing oninfinity, and 56B are graphs showing various aberrations upon focusingon a close object;

FIG. 57 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-4;

FIGS. 58A and 58B are graphs showing various aberrations of Example 4-4,where 58A are graphs showing various aberrations upon focusing oninfinity, and 58 are graphs showing various aberrations upon focusing ona close object;

FIG. 59 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-5;

FIGS. 60A and 60B are graphs showing various aberrations of Example 4-5,where 60A are graphs showing various aberrations upon focusing oninfinity, and 60B are graphs showing various aberrations upon focusingon a close object;

FIG. 61 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-6;

FIGS. 62A and 62B are graphs showing various aberrations of Example 4-6,where 62A are graphs showing various aberrations upon focusing oninfinity, and 62B are graphs showing various aberrations upon focusingon a close object;

FIG. 63 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-7;

FIGS. 64A and 64B are graphs showing various aberrations of Example 4-7,where 64A are graphs showing various aberrations upon focusing oninfinity, and 64B are graphs showing various aberrations upon focusingon a close object;

FIG. 65 is a cross-sectional view depicting a configuration of theimaging lens according to Example 4-8;

FIGS. 66A and 663 are graphs showing various aberrations of Example 4-8,where 66A are graphs showing various aberrations upon focusing oninfinity, and 66B are graphs showing various aberrations upon focusingon a close object; and

FIG. 67 is a flow chart depicting a method for manufacturing the imaginglens.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments will now be described with reference to thedrawings.

First a configuration of a digital still camera 1 is shown in FIGS. 1Aand 1B and FIG. 2 as an optical apparatus having an imaging lens SLaccording to an embodiment of the present invention. In this digitalstill camera 1, an unillustrated shutter is opened when an unillustratedpower button is pressed, and lights from an unillustrated object arecondensed by the imaging lens SL, and forms an image on an image sensingelement C (e.g. film, CCD, CMOS) disposed on an image plane I. Theobject image formed on the image sensing element C is displayed on aliquid crystal monitor 2 which is disposed on the back of the camera 1.The user decides on a composition of the object image while checking theliquid crystal monitor 2, and presses down on a release button 3. Thenthe object image is captured by the image sensing element C, and isrecorded and stored in an unillustrated memory.

In this digital still camera 1, an auxiliary light emission unit 4 thatemits an auxiliary light when an object is dark, a wide (W)-tele (T)button 5 that is used to zoom a zooming optical system ZL from a wideangle end state (W) to a telephoto end state (T), a function button 6that is used for setting various conditions of the digital still camera1, and other components, are disposed. The present invention is notlimited to the camera of this embodiment, and the imaging lens SL canalso be applied to an interchangeable lens.

First Embodiment

A first embodiment of the imaging lens according to the presentinvention will now be described. The first embodiment includes examples(Example 1-1 to Example 1-8) herein below.

The imaging lens SL according to the first embodiment includesconfigurations of Examples 1-1 to 1-8 shown in FIG. 3, FIG. 5, FIG. 7,FIG. 9, FIG. 11, FIG. 13, FIG. 15 and FIG. 17, but is described usingthe configuration in FIG. 3 as an example. As shown in FIG. 3, thisimaging lens SL comprises a first lens group G1 having a positiverefractive power, an aperture stop S, and a second lens group G2 havinga positive refractive power, which are disposed in order from an object,wherein the first lens group G1 further comprises a first lens componentL1 having a negative refractive power, and a second lens component L2having a positive refractive power which are disposed in order from theobject, and the second lens group G2 further comprises at least onecemented lens (cemented lens L34 in FIG. 3). Because of thisconfiguration, the imaging lens SL according to the first embodiment, ofwhich angle of view exceeds 60° and which is compact and can implementexcellent image forming performance, can be created.

In the first embodiment having the above configuration, a sphericalaberration and coma aberration, which are generated in the first lensgroup G1 alone, are minimized, so conditions expressed by the followingexpressions (1) and (2)0.12<f/f1<0.47  (1)0.016<D12/f<0.079  (2)are satisfied, where f1 is a focal length of the first lens group G1, fis a focal length of the imaging lens, and D12 is an air distance(distance on the optical axis) between the first lens component L1 andthe second lens component L2 of the first lens group G1.

The conditional expression (1) is a conditional expression to specify anappropriate range of the focal length f1 of the first lens group G1 andthe focal length f of the imaging lens. If the upper limit value of theconditional expression (1) is exceeded, it becomes difficult to correctthe spherical aberration and coma aberration which are generated in thefirst lens group G1 alone. If the lower limit value of the conditionalexpression (1) is not reached, on the other hand, the focal length f1 ofthe first lens group G1 increases, and this is an advantage forcorrecting Aberrations, but increases the total length of the lenssystem, which runs counter to the intent of the present invention, andis therefore not preferable.

To make the effect of the first embodiment certain, it is preferablethat the upper limit value of the conditional expression (1) is 0.45. Tomake the effect of the first embodiment more certain, it is preferablethat the upper limit value of the conditional expression (1) is 0.42. Tomake the effect of the first embodiment even more certain, it ispreferable that the upper limit value of the conditional expression (1)is 0.39.

To make the effect of the first embodiment certain, it is preferablethat the lower limit value of the conditional expression (1) is 0.15. Tomake the effect of the first embodiment more certain, it is preferablethat the lower limit value of the conditional expression (1) is 0.18.

The conditional expression (2) is a conditional expression to specify anappropriate range of an air distance D12 between the first lenscomponent L1 and the second lens component L2 of the first lens groupG1. If the upper limit value of the conditional expression (2) isexceeded, the spherical aberration and coma aberration can be correctedsatisfactorily, but the entire first lens group G1 becomes thicker. As aresult, the total length of the lens system increases, which runscounter to the intent of the present invention. If the lower limit valueof the conditional expression (2) is not reached, on the other hand,this is an advantage to downsize, but makes correction of a comaaberration difficult, which is not preferable.

To make the effect of the first embodiment certain, it is preferablethat the upper limit value of the conditional expression (2) is 0.075.To make the effect of the first embodiment more certain, it ispreferable that the upper limit value of the conditional expression (2)is 0.071. To make the effect of the first embodiment even more certain,it is preferable that the upper limit value of the conditionalexpression (2) is 0.067.

To make the effect of the first embodiment certain, it is preferablethat the lower limit value of the conditional expression (2) is 0.020.To make the effect of the first embodiment more certain, it ispreferable that the lower limit value of the conditional expression (2)is 0.025.

In the first embodiment, it is preferable that the first lens group G1further has a first lens component L1 of a negative meniscus lens havinga convex surface facing the object, and a second lens component L2 of apositive meniscus lens having a convex surface facing the object, whichare disposed in order from the object. Because of this configuration, inthe imaging lens SL of the first embodiment, the higher performance anddownsizing can be balanced, and the spherical aberration and curvatureof field generated in the first lens group G1 alone can be correctedsatisfactorily.

In the first embodiment, it is preferable that a condition expressed bythe following expression (3)nd1>1.65  (3)is satisfied, where nd1 is a refractive index of the first lenscomponent L1 of the first lens group G1 on the d-line.

The conditional expression (3) is a conditional expression to specifyoptical material characteristics of the first lens component L1 of thefirst lens group G1. If the lower limit value of the conditionalexpression (3) is not reached, correction of the coma aberration becomesdifficult, and high performance cannot be implemented, which is notpreferable.

To make the effect of the present invention certain, it is preferablethat the lower limit value of the conditional expression (3) is 1.655.To make the effect of the present invention more certain, it ispreferable that the lower limit value of the conditional expression (3)is 1.660. To make the effect of the present invention even more certain,it is preferable that the lower limit value of the conditionalexpression (3) is 1.665.

In the first embodiment, it is preferable that the condition expressedby the following expression (4)3.8<(r2F+r1R)/(r2F−r1R)<11.8  (4)is satisfied, where r1R is a radius of curvature of the image side lenssurface of the first component L1, and r2F is a radius of curvature ofthe object side lens surface of the second lens component L2.

The conditional expression (4) is a conditional expression to correctthe coma aberration and curvature of field generated in the first lensgroup G1 alone satisfactorily. If the upper limit value of theconditional expression (4) is exceeded, the coma Aberration andcurvature of field generated in the first lens group G1 alone cannot becorrected. Distortion also increases, which is not preferable. If thelower limit value of the conditional expression (4) is not reached, onthe other hand, the coma aberration generated in the first lens group G1alone increases too much, and performance in the shortest photographicdistance deteriorates, which is not preferable.

To make the effect of the first embodiment certain, it is preferablethat the upper limit value of the conditional expression (4) is 11.0. Tomake the effect of the first embodiment more certain, it is preferablethat the upper limit value of the conditional expression (4) is 10.5. Tomake the effect of the first embodiment even more certain, it ispreferable that the upper limit value of the conditional expression (4)is 10.0.

To make the effect of the first embodiment certain, it is preferablethat the lower limit value of the conditional expression (4) is 4.3. Tomake the effect of the first embodiment more certain, it is preferablethat the lower limit value of the conditional expression (4) is 4.8. Tomake the effect of the first embodiment even more certain, it ispreferable that the lower limit value of the conditional expression (4)is 5.3.

In the first embodiment, it is preferable that the first lens group G1includes at least one aspherical surface (second surface from the objectin FIG. 3). Because of this configuration, higher performance anddownsizing can be balanced, and the spherical aberration and curvatureof field can be corrected satisfactorily.

In the first embodiment, it is preferable that the first lens componentof the first lens group G1 includes at least one aspherical surface(second surface from the object in FIG. 3). Because of thisconfiguration, higher performance and downsizing can be balanced, andthe spherical aberration and curvature of field can be correctedsatisfactorily.

In the first embodiment, it is preferable that the second lens group G2further comprises a cemented lens L34 of a negative lens L3 having aconcave surface facing the object and a positive lens L4 having a convexsurface facing the image, and a biconvex positive lens L5, which aredisposed in order from the object. Because of this configuration, thecurvature of field and coma Aberration can be corrected satisfactorily,and higher performance of the imaging lens SL can be implemented.

In the first embodiment, it is preferable that the second lens group G2includes at least one aspherical surface (twelfth surface from theobject in FIG. 3). Because of this configuration, fluctuation ofdistortion and curvature of field generated upon focusing can becorrected satisfactorily, and higher performance of the imaging lens SLcan be implemented.

In the first embodiment, it is preferable that the second lens group G2further comprises a biconvex positive lens L5, and this biconvexpositive lens L5 includes at least one aspherical surface (twelfthsurface of the object in FIG. 3). Because of this configuration,fluctuation of distortion and curvature of field generated upon focusingcan be corrected satisfactorily, and higher performance of the imaginglens SL can be implemented.

In the first embodiment, it is preferable that focus on a close objectis adjusted by moving the second lens group G2 toward the object.Because of this configuration, fluctuation of aberration upon focusadjustment can be suppressed, and interference of a lens or mechanicalcomponent to support a lens can be prevented, since a feed pitch of thesecond lens group G2 toward the object upon focus adjustment is verysmall. It is possible to adjust focus on a close object using the firstlens group G1, but a feed pitch toward the object becomes very large,which causes a change in the total length of the lens. Along with thischange, such a mechanism as the drive system becomes complicated, anddownsizing becomes difficult. Also deterioration of the sphericalaberration and curvature of field increase, which is not preferable.

In the first embodiment, in order to prevent failure of photography dueto an image blur caused by camera motion, it is possible that a blurdetection system for detecting the blur of the lens system and the drivemeans are combined in the lens system, and all or a part of one lensgroup, out of the lens groups constituting the lens system, aredecentered as a shift lens group, and an image is shifted by driving theshift lens group by the drive means so as to correct the image blur(fluctuation of image plane position) caused by the blur of the lenssystem detected by the blur detection system, thereby the image blur canbe corrected. As mentioned above, the imaging lens SL of the firstembodiment can function as a vibration proof optical system.

The imaging lens SL according to the first embodiment comprises two lensgroups, that is, the first lens group G1 and the second lens group G2,but another lens group may be added between the lens groups or anotherlens group may be added at the image side of the first lens group G1, orat the object side of the second lens group G2.

In the imaging lens SL according to the first embodiment, it ispreferable that the distance from the image side lens surface to theimage plane (back focus) of the positive lens L5 disposed closest to theimage is about 10 to 30 mm in the shortest state. In the imaging lensSL, it is preferable that the image height is 5 to 12.5 mm, and morepreferably is 5 to 9.5 mm.

The following can be implemented when appropriate within a range wherethe optical performance of the imaging lens according to the firstembodiment is not diminished. These matters can also be implemented forthe later mentioned second to fourth embodiments when appropriate.

The first embodiment, where two-group configuration is shown, can alsobe applied to other configurations, such as a three-group configuration.For example, a configuration where a lens group having a positiverefractive power comprising a biconvex single lens disposed closest tothe image, can be used.

Also in the first embodiment, a single or a plurality of lens groups, ora part of a lens group, may be constructed as a focusing lens group,where focusing from an object at infinity to a close object is performedby moving the lens group in an optical axis direction. The focusing lensgroup can also be applied to auto focus, and is also appropriate for thedriving motor for auto focus (using a stepping motor or ultra sonicmotor). It is particularly preferable to construct the second lens groupG2 as the focusing lens group.

Also in the first embodiment, a lens group or a part of a lens group maybe a vibration proof lens group that corrects an image blur caused by acamera motion blur, by moving the lens group in a directionperpendicular to the optical axis. In particular, it is preferable thatat least a part of the second lens group G2 is a vibration proof lensgroup.

Also in the first embodiment, the lens surfaces may be aspherical. Theaspherical surface may be an aspherical surface created by grinding, aglass mold aspherical surface where glass is formed to be asphericalusing a die, or a composite aspherical surface where resin is formed tobe an aspherical shape on the surface of glass. The lens surfaces may bea diffraction surface, and the lenses may be a refractive indexdistributed lens (GRIN lens) or a plastic lens.

Also in the first embodiment, it is preferable that the aperture stop Sis disposed between the first lens group G1 and the second lens groupG2, but the frame of the lens may substitute for this role withoutdisposing an aperture stop as a separate element.

Also in the first embodiment, it is preferable that a flare cut stop(flare cut stops S1 and S2 in FIG. 3) is disposed between the first lensgroup G1 and the second lens group G2, but the frame of the lens maysubstitute for this role without disposing a flare cut stop as aseparate element.

Also in the first embodiment, an anti-reflection film having a hightransmittance in a wide wavelength area may be formed on each lenssurface constituting the imaging lens SL, so as to decrease flares andghosts, and to implement high optical performance with high contrast.

In the imaging lens SL of the first embodiment, a focal length,converted into 35 mm film size, is about 38 mm (35 to 43 mm), and the Fnumber is about 2.8 (2.5 to 3.3).

In the imaging lens SL of the first embodiment, it is preferable thatthe first lens group G1 further comprises one positive lens componentand one negative lens component. It is preferable that the lenscomponents of the first lens group G1 are disposed in order of negativeand positive from the object, with air distance there between.

In the imaging lens SL of the first embodiment, it is preferable thatthe second lens group G2 further comprises two positive lens componentsand one negative lens component. It is also preferable that the lenscomponents of the second lens group G2 are disposed in order ofnegative, positive and positive from the object.

According to the first embodiment, variant forms of the first lens groupG1 are, for example, using a cemented lens for the second lens componentL2, adding a positive or a negative lens at the object side of the firstlens component L1, and adding a positive or negative lens at the imageside of the second lens component L2.

Also according to the first embodiment, variant forms of the second lensgroup G2 are, for example, constructing the cemented lens L34 with threelenses, using a cemented lens for the fifth lens component L5, andseparating the cemented lens L34 and constructing the third lenscomponent L3 and the fourth lens component L4 as single lensesrespectively. The refractive power of the cemented lens L34 can bepositive or negative.

Examples of the First Embodiment

Example 1-1 to Example 1-8 according to the first embodiment will now bedescribed with reference to the drawings. FIG. 3, FIG. 5, FIG. 7, FIG.9, FIG. 11, FIG. 13, FIG. 15 and FIG. 17 are cross-sectional viewsdepicting a configuration of the imaging lens SL (SL1 to SL8) accordingto each example, where the change of focusing state, from focusing oninfinity to focusing on a close object of the imaging lenses SL1 to SL8,that is, the state of movement of each lens group upon focusing, isshown by an arrow.

As described above, the imaging lens SL1 to SL8 according to eachexample comprises a first lens group G1 having a positive refractivepower, an aperture stop S, a second lens group G2 having a positiverefractive power, and a filter group FL which includes a low passfilter, infrared cut filter or the like, which are disposed in orderfrom an object. Upon focusing from the state of focusing on infinity tothe state of focusing on a close object, the first lens group G1 isfixed with respect to the image plane I, and the second lens group G2 ismoved with respect to the image plane I, so as to change the distancebetween the first lens group G1 and the second lens group G2. The imageplane I is formed on an unillustrated image sensing element, and thisimage sensing element is CCD or CMOS, for example.

Table 1-1 to Table 1-8 shown below are tables of each parameteraccording to Example 1-1 to Example 1-8. In [surface data] in thetables, the surface number is a sequence of a lens surface counted fromthe object side along the traveling direction of the light, r is aradius of curvature of each lens surface, d is a surface distance, whichis a distance from each optical surface to the next optical surface (orimage plane) on the optical axis, nd is a refractive index on the d-line(wavelength: 587.6 nm), and νd is an Abbe number with respect to thed-line. di (i is an integer) is a variable surface distance of the i-thsurface and Bf is a back focus. If the lens surface is aspherical, “*”is attached to the surface number, and a paraxial radius of curvature isshown in the column of the radius of curvature r. “0.0000” of the radiusof curvature r indicates a plane or aperture. The refractive index ofair “1.00000” is omitted.

In [aspherical data], the shape of the aspherical surface shown in[surface data] is given by the following expression (a). Here y is aheight in a direction perpendicular to the optical axis, S(y) is adistance along the optical axis from the tangential plane at the vertexof the aspherical surface to a position on the aspherical surface at theheight y (Sag amount), r is a radius of curvature of a referencespherical surface (paraxial radius of curvature), κ is a conicalcoefficient, and Cn is an aspherical coefficient of degree n. In eachexample, C₂, the aspherical coefficient of degree 2, is 0. En indicates×10^(n). For example, 1.234 E-05=1.234×10⁻⁵.S(y)=(y ² /r)/{1+(1−κ·y ² /r ²)^(1/2) }+C4×y ⁴ +C6×y ⁶ +C8×y ⁸ +C10×y¹⁰  (a)

In [various data], f is a focal length of the imaging lens, FNO is an Fnumber, 2ω is an angle of view, Y is an image height, and TL is a totallength of the lens system (distance on the optical axis from the lenssurface closest to the object to the image plane). In [variable distancedata], f is a focal length of the imaging lens, β is magnification, di(i is an integer) is a variable surface distance of the i-th surface inthe state of focusing on infinity and the state of focusing on a closeobject (0.2 m photographic distance (distance from the object to theimage plane)). In [conditional expression], values corresponding to theexpressions (1) to (4) are shown.

In the tables, “mm” is used for the unit of focal length f, radius ofcurvature r, surface distance d and other lengths. However unit is notlimited to “mm”, but another appropriate unit can be used, since theoptical system can obtain an equivalent optical performance, even if itis proportionately expanded or reduced.

The above description on the tables is the same for other embodimentsand other examples, therefore description thereof will be omitted hereinbelow.

Example 1-1

The imaging lens SL1 according to Example 1-1 will now be described withreference to FIG. 3, FIGS. 4A, and 4B and Table 1-1. As FIG. 3 shows, inthe imaging lens SL1 according to Example 1-1, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-1, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-1 shows a table on each parameter of Example 1-1. The surfacenumbers 1 to 18 in Table 1-1 correspond to the surfaces 1 to 18 in FIG.3. In Example 1-1, the second surface and the twelfth surface areaspherical.

TABLE 1-1 [Surface data] Surface number r d nd νd 1 12.5540 0.90 1.6779054.89 *2 5.1200 0.80 3 7.2279 1.90 1.88300 40.76 4 25.2952 0.80 5 0.00001.40 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.00(Flare stop S2) 8 −5.1593 0.90 1.80810 22.76 9 −15.0968 2.65 1.7550052.32 10 −6.5278 0.20 11 25.0474 2.70 1.58913 61.16 *12 −19.8008 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.1200 κ = +0.9952 C4 = −3.5496E−04 C6 =−1.3835E−05 C8 = −6.4411E−08 C10 = −2.8213E−08 Twelfth surface r =−19.8008 κ = +5.2781 C4 = +2.1953E−04 C6 = −1.0580E−07 C8 = +2.9574E−08C10 = −2.6872E−10 [Various data] f = 14.26 FNO = 2.83 2ω = 62.12 Y =8.50 TL = 31.51 [Variable distance data] Infinity Close Object d6 1.85140.6000 d12 10.4286 11.6800 Bf 0.5058 0.5058 [Lens group data] Firstsurface Focal length First lens group 1 58.2236 Second lens group 714.9735 [Conditional expression] nd1 = 1.67790 f = 14.2560 f1 = 58.2236D12 = 0.8000 r1R = 5.1200 r2F = 7.2279 Conditional expression (1) f/f1 =0.2448 Conditional expression (2) D12/f = 0.0561 Conditional expression(3) nd1 = 1.67790 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =5.8579

As the parameter table in Table 1-1 shows, the imaging lens SL1according to Example 1-1 satisfies all the conditional expressions (1)to (4).

FIGS. 4A and 4B are graphs showing various aberrations of the imaginglens SL1 according to Example 1-1, where FIG. 4A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 4B are graphsshowing various aberrations upon focusing on a close object. In eachgraph showing aberrations, NA is a numerical aperture, FNO is an Fnumber, A is a half angle of view, and HO is a height of an object. dindicates aberrations on the d-line (wavelength: 587.6 nm), g indicatesaberrations on the g-line (wavelength: 435.8 nm), C indicatesaberrations with respect to the C-line (wavelength: 656.3 nm), and Findicates aberrations on the F-line (wavelength: 486.1 nm), and a valuewith no indication is a value with respect to the d-line. In a graphshowing astigmatism, a solid line indicates a sagittal image surface,and a broken line indicates a meridional image surface.

The above description on graphs showing aberrations is the same forother examples, therefore description thereof is omitted.

As each graph showing aberrations shows, according to the imaging lensSL1 of the Example 1-1, various aberrations can be correctedsatisfactorily from a state of focusing on infinity to a state offocusing on a close object, and excellent image forming performance isimplemented.

Example 1-2

The imaging lens SL2 according to Example 1-2 will now be described withreference to FIG. 5, FIGS. 6A and 6B and Table 1-2. As FIG. 5 shows, inthe imaging lens SL2 according to Example 1-2, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-2, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-2 shows a table on each parameter of Example 1-2. The surfacenumbers 1 to 18 in Table 1-2 correspond to the surfaces 1 to 18 in FIG.5. In Example 1-2, the second surface and the twelfth surface areaspherical.

TABLE 1-2 [Surface data] Surface number r d nd νd 1 11.8261 0.90 1.6779054.89 *2 5.0108 0.65 3 7.0263 1.85 1.88300 40.76 4 23.3567 0.70 5 0.00001.40 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.00(Flare stop S2) 8 −5.0661 0.90 1.80810 22.76 9 −14.6310 2.70 1.7550052.32 10 −6.3977 0.20 11 23.5294 2.70 1.58913 61.16 *12 −21.4493 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.0108 κ = +0.1277 C4 = +4.8479E−04 C6 =+5.6078E−06 C8 = +1.1439E−07 C10 = +2.6889E−09 Twelfth surface r =−21.4493 κ = −5.6807 C4 = +6.6823E−05 C6 = −6.8560E−08 C8 = +2.3185E−08C10 = −3.6236E−10 [Various data] f = 14.26 FNO = 2.88 2ω = 62.12 Y =8.50 TL = 31.01 [Variable distance data] Infinity Close Object d6 1.85080.6000 d12 10.1792 11.4301 Bf 0.5070 0.5070 [Lens group data] Firstsurface Focal length First lens group 1 56.8827 Second lens group 714.7636 [Conditional expression] nd1 = 1.67790 f = 14.2560 f1 = 56.8827D12 = 0.6500 r1R = 5.0108 r2F = 7.0263 Conditional expression (1) f/f1 =0.2506 Conditional expression (2) D12/f = 0.0456 Conditional expression(3) nd1 = 1.67790 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =5.9722

As the parameter table in Table 1-2 shows, the imaging lens SL2according to Example 1-2 satisfies all the conditional expressions (1)to (4).

FIGS. 6A and 6B are graphs showing various aberrations of the imaginglens SL2 according to Example 1-2, where FIG. 6A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 6B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL2 ofthe Example 1-2, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Example 1-3

The imaging lens SL3 according to Example 1-3 will now be described withreference to FIG. 7, FIGS. 8A and 8B and Table 1-3. As FIG. 7 shows, inthe imaging lens SL3 according to Example 1-3, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-3, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-3 shows a table on each parameter of Example 1-3. The surfacenumbers 1 to 18 in Table 1-3 correspond to the surfaces 1 to 18 in FIG.7. In Example 1-3, the second surface and the twelfth surface areaspherical.

TABLE 1-3 [Surface data] Surface number r d nd νd 1 12.6464 0.90 1.6691055.42 *2 5.7001 0.75 3 7.7231 1.67 1.88300 40.76 4 24.6238 0.20 5 0.00001.40 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.50(Flare stop S2) 8 −5.0699 0.90 1.80810 22.76 9 −18.5950 3.00 1.8040046.57 10 −7.0355 0.20 11 26.7580 3.12 1.61881 63.85 *12 −18.8179 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.7001 κ = +1.7002 C4 = −7.4793E−04 C6 =−3.1424E−05 C8 = +2.0843E−07 C10 = −1.3010E−07 Twelfth surface r =−18.8179 κ = −7.0961 C4 = −3.0038E−05 C6 = +1.0404E−06 C8 = −1.2568E−09C10 = −4.7030E−11 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y =8.50 TL = 32.01 [Variable distance data] Infinity Close Object d6 2.41971.1500 d12 9.9683 11.2380 Bf 0.5123 0.5123 [Lens group data] Firstsurface Focal length First lens group 1 48.8782 Second lens group 714.6742 [Conditional expression] nd1 = 1.66910 f = 14.2560 f1 = 48.8782D12 = 0.7500 r1R = 5.7001 r2F = 7.7231 Conditional expression (1) f/f1 =0.2917 Conditional expression (2) D12/f = 0.0526 Conditional expression(3) nd1 = 1.66910 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =6.6351

As the parameter table in Table 1-3 shows, the imaging lens SL3according to Example 1-3 satisfies all the conditional expressions (1)to (4).

FIGS. 8A and 8B are graphs showing various aberrations of the imaginglens SL3 according to Example 1-3, where FIG. 8A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 8B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL3 ofthe Example 1-3, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Example 1-4

The imaging lens SL4 according to Example 1-4 will now be described withreference to FIG. 9, FIGS. 10A and 10B and Table 1-4. As FIG. 9 shows,in the imaging lens SL4 according to Example 1-4, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-4, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-4 shows a table on each parameter of Example 1-4. The surfacenumbers 1 to 18 in Table 1-4 correspond to the surfaces 1 to 18 in FIG.9. In Example 1-4, the second surface and the twelfth surface areaspherical.

TABLE 1-4 [Surface data] Surface number r d nd νd 1 9.9874 0.90 1.6889331.08 *2 5.0739 0.45 3 6.3837 1.76 1.85026 32.35 4 17.4312 0.30 5 0.00001.95 (Flare stop S1) 6 0.0000 0.45 (Aperture stop S) 7 0.0000 1.50(Flare stop S2) 8 −4.8003 0.90 1.80810 22.76 9 −18.5588 2.98 1.8160046.62 10 −6.7015 0.20 11 20.2148 2.86 1.66910 55.42 *12 −30.3443 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.0739 κ = −2.9635 C4 = +3.4708E−03 C6 =−1.4779E−04 C8 = +8.3851E−06 C10 = −2.3110E−07 Twelfth surface r =−30.3443 κ = −0.7304 C4 = +1.2477E−04 C6 = +4.7254E−07 C8 = +9.6784E−09C10 = −1.1595E−10 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y =8.50 TL = 30.00 [Variable distance data] Infinity Close Object d6 1.74730.4500 d12 8.4731 9.7704 Bf 0.4998 0.4998 [Lens group data] Firstsurface Focal length First lens group 1 38.8259 Second lens group 714.1972 [Conditional expression] nd1 = 1.68893 f = 14.2560 f1 = 39.8259D12 = 0.4500 r1R = 5.0739 r2F = 6.3837 Conditional expression (1) f/f1 =0.3580 Conditional expression (2) D12/f = 0.0316 Conditional expression(3) nd1 = 1.68893 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =8.7473

As the parameter table in Table 1-4 shows, the imaging lens SL4according to Example 1-4 satisfies all the conditional expressions (1)to (4).

FIGS. 10A and 10B are graphs showing various aberrations of the imaginglens SL4 according to Example 1-4, where FIG. 10A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 10B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL4 ofthe Example 1-4, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Example 1-5

The imaging lens SL5 according to Example 1-5 will now be described withreference to FIG. 11, FIGS. 12A and 12B and Table 1-5. As FIG. 11 shows,in the imaging lens SL5 according to Example 1-5, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-5, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-5 shows a table on each parameter of Example 1-5. The surfacenumbers 1 to 18 in Table 1-5 correspond to the surfaces 1 to 18 in FIG.11. In Example 1-5, the second surface and the twelfth surface areaspherical.

TABLE 1-5 [Surface data] Surface number r d nd νd 1 9.3520 0.90 1.6779054.89 *2 4.8208 0.45 3 5.9177 1.85 1.81600 46.62 4 15.9734 0.35 5 0.00001.95 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.60(Flare stop S2) 8 −4.6847 0.90 1.80810 22.76 9 −18.5193 3.04 1.8160046.62 10 −6.7523 0.20 11 19.5054 3.10 1.66910 55.42 *12 −28.1863 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 4.8208 κ = −2.2502 C4 = +3.2855E−03 C6 =−1.1017E−04 C8 = +6.2421E−06 C10 = −1.6029E−07 Twelfth surface r =−28.1863 κ = +3.4908 C4 = +1.4959E−04 C6 = −3.4328E−07 C8 = +5.0300E−09C10 = −5.9841E−11 [Various data] f = 14.26 FNO = 2.92 2ω = 62.12 Y =8.50 TL = 30.00 [Variable distance data] Infinity Close Object d6 1.61520.3000 d12 8.0762 9.3915 Bf 0.4989 0.4989 [Lens group data] Firstsurface Focal length First lens group 1 36.9620 Second lens group 714.0056 [Conditional expression] nd1 = 1.67790 f = 14.2560 f1 = 36.9620D12 = 0.4500 r1R = 4.8208 r2F = 5.9177 Conditional expression (1) f/f1 =0.3857 Conditional expression (2) D12/f = 0.0316 Conditional expression(3) nd1 = 1.67790 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =9.7901

As the parameter table in Table 1-5 shows, the imaging lens SL5according to Example 1-5 satisfies all the conditional expressions (1)to (4).

FIGS. 12A and 12B are graphs showing various aberrations of the imaginglens SL5 according to Example 1-5, where FIG. 12A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 12B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL5 ofthe Example 1-5, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Example 1-6

The imaging lens SL6 according to Example 1-6 will now be described withreference to FIG. 13, FIGS. 14A and 14B and Table 1-6. As FIG. 13 shows,in the imaging lens SL6 according to Example 1-6, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-6, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-6 shows a table on each parameter of Example 1-6. The surfacenumbers 1 to 18 in Table 1-6 correspond to the surfaces 1 to 18 in FIG.13. In Example 1-6, the second surface and the twelfth surface areaspherical.

TABLE 1-6 [Surface data] Surface number r d nd νd 1 8.7469 0.90 1.6779054.89 *2 4.6799 0.45 3 5.8268 1.85 1.81600 46.62 4 14.7269 0.35 5 0.00001.95 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.45(Flare stop S2) 8 −4.7008 0.90 1.80810 22.76 9 −19.5674 3.05 1.8160046.62 10 −6.8100 0.20 11 20.7908 3.10 1.66910 55.42 *12 −24.7647 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 4.6799 κ = −1.0342 C4 = +2.1291E−03 C6 =−2.5886E−05 C8 = +2.2070E−06 C10 = −5.3593E−08 Twelfth surface r =−24.7647 κ = −7.3551 C4 = +6.0709E−05 C6 = +1.2096E−08 C8 = +2.7737E−09C10 = −5.6169E−11 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y =8.50 TL = 30.00 [Variable distance data] Infinity Close Object d6 1.65750.3500 d12 8.1725 9.4800 Bf 0.4953 0.4953 [Lens group data] Firstsurface Focal length First lens group 1 37.8004 Second lens group 713.8767 [Conditional expression] nd1 = 1.67790 f = 14.2560 f1 = 37.8004D12 = 0.4500 r1R = 4.6800 r2F = 5.8268 Conditional expression (1) f/f1 =0.3771 Conditional expression (2) D12/f = 0.0316 Conditional expression(3) nd1 = 1.67790 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =9.1613

As the parameter table in Table 1-6 shows, the imaging lens SL6according to Example 1-6 satisfies all the conditional expressions (1)to (4).

FIGS. 14A and 14B are graphs showing various aberrations of the imaginglens SL6 according to Example 1-6, where FIG. 14A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 14B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL6 ofthe Example 1-6, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Example 1-7

The imaging lens SL7 according to Example 1-7 will now be described withreference to FIG. 15, FIGS. 16A and 16B and Table 1-7. As FIG. 15 shows,in the imaging lens SL7 according to Example 1-7, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-7, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-7 shows a table on each parameter of Example 1-7. The surfacenumbers 1 to 18 in Table 1-7 correspond to the surfaces 1 to 18 in FIG.15. In Example 1-7, the second surface and the twelfth surface areaspherical.

TABLE 1-7 [Surface data] Surface number r d nd νd 1 14.0147 0.90 1.6779054.89 *2 5.4694 0.90 3 7.6437 1.75 1.88300 40.76 4 30.8895 0.25 5 0.00001.60 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.25(Flare stop S2) 8 −5.1623 0.95 1.80810 22.76 9 −14.4718 2.75 1.7550052.32 10 −6.7218 0.20 11 26.5149 2.85 1.59201 67.02 *12 −18.8905 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.4694 κ = +1.4173 C4 = −6.4702E−04 C6 =−2.1283E−05 C8 = −4.5161E−07 C10 = −6.2922E−08 Twelfth surface r =−18.8905 κ = +5.5850 C4 = +2.2637E−04 C6 = +8.5167E−07 C8 = +1.1963E−08C10 = +1.5290E−10 [Various data] f = 14.26 FNO = 2.83 2ω = 62.07 Y =8.50 TL = 32.01 [Variable distance data] Infinity Close Object d6 2.06760.8000 d12 10.5324 11.8300 Bf 0.5145 0.5145 [Lens group data] Firstsurface Focal length First lens group 1 51.9495 Second lens group 715.2959 [Conditional expression] nd1 = 1.67790 f = 14.2560 f1 = 51.9495D12 = 0.9000 r1R = 5.4694 r2F = 7.6437 Conditional expression (1) f/f1 =0.2744 Conditional expression (2) D12/f = 0.0631 Conditional expression(3) nd1 = 1.67790 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =6.0310

As the parameter table in Table 1-7 shows, the imaging lens SL7according to Example 1-7 satisfies all the conditional expressions (1)to (4).

FIGS. 16A and 16B are graphs showing various aberrations of the imaginglens SL7 according to Example 1-7, where FIG. 16A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 16B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL7 ofthe Example 1-7, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Example 1-8

The imaging lens SL8 according to Example 1-8 will now be described withreference to FIG. 17, FIGS. 18A and 18B and Table 1-8. As FIG. 17 shows,in the imaging lens SL8 according to Example 1-8, a first lens group G1comprises a negative meniscus lens L1 (first lens component) having aconvex surface facing the object, and a positive meniscus lens L2(second lens component) having a convex surface facing the object, whichare disposed in order from the object. A second lens group G2 comprisesa cemented lens L34 of a negative meniscus lens L3 having a concavesurface facing the object and a positive meniscus lens L4 having aconvex surface facing the image, and a biconvex positive lens L5, whichare disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost-positions of the aperture stop S.

In Example 1-8, an axial air distance d6 between the first lens group G1and the second lens group G2, and an axial air distance d12 between thesecond lens group G2 and the filter group FL, change upon focusing.

Table 1-8 shows a table on each parameter of Example 1-8. The surfacenumbers 1 to 18 in Table 1-8 correspond to the surfaces 1 to 18 in FIG.17. In Example 1-8, the second surface and the twelfth surface areaspherical.

TABLE 1-8 [Surface data] Surface number r d nd νd 1 14.0077 1.30 1.6779054.89 *2 5.3933 0.60 3 7.5715 1.95 1.88300 40.76 4 28.3663 0.25 5 0.00001.75 (Flare stop S1) 6 0.0000 (d6) (Aperture stop S) 7 0.0000 1.25(Flare stop S2) 8 −5.2273 0.98 1.80810 22.76 9 −15.1471 2.88 1.7550052.32 10 −6.7013 0.20 11 23.0044 2.94 1.59201 67.02 *12 −20.7345 8.96 130.0000 0.50 1.51633 64.14 14 0.0000 4.60 15 0.0000 1.87 1.51633 64.14 160.0000 0.30 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.3933 κ = +1.7327 C4 = −9.1467E−04 C6 =−4.4123E−05 C8 = +8.7126E−07 C10 = −2.7436E−07 Twelfth surface r =−20.7345 κ = −19.0000 C4 = −1.4487E−04 C6 = +4.4684E−06 C8 = −5.5750E−08C10 = +3.1253E−10 [Various data] f = 14.26 FNO = 2.92 2ω = 62.50 Y =8.50 TL = 32.36 [Variable distance data] Infinity Close Object d6 2.03760.8000 d12 7.7203 8.9579 Bf 0.5348 0.5348 [Lens group data] Firstsurface Focal length First lens group 1 51.9495 Second lens group 714.3554 [Conditional expression] nd1 = 1.67790 f = 14.2560 f1 = 67.2632D12 = 0.6000 r1R = 5.3933 r2F = 7.5715 Conditional expression (1) f/f1 =0.2119 Conditional expression (2) D12/f = 0.0421 Conditional expression(3) nd1 = 1.67790 Conditional expression (4) (r2F + r1R)/(r2F − r1R) =5.9520

As the parameter table in Table 1-8 shows, the imaging lens SL8according to Example 1-8 satisfies all the conditional expressions (1)to (4).

FIGS. 18A and 18B are graphs showing various aberrations of the imaginglens SL8 according to Example 1-8, where FIG. 18A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 18B are graphsshowing various aberrations upon focusing on a close object. As eachgraph showing aberrations shows, according to the imaging lens SL8 ofthe Example 1-8, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent image forming performance is implemented.

Second Embodiment

A second embodiment of the imaging lens according to the presentinvention will now be described. The second embodiment includes examples(Example 2-1 to Example 2-8) herein below.

The imaging lens SL according to the second embodiment includesconfigurations of Example 2-1 to Example 2-8 shown in FIG. 19, FIG. 21,FIG. 23, FIG. 25, FIG. 27, FIG. 29, FIG. 31 and FIG. 33, but isdescribed using the configuration in FIG. 19 as an example. This imaginglens SL comprises a first lens group G1 having a positive refractivepower, and a second lens group G2 having a positive refractive power,which are disposed in order from an object, wherein the first lens groupG1 further comprises a plurality of lenses (two lenses, lens L1 and lensL2 in FIG. 19), and the second lens group G2 further comprises acemented lens L34 of a negative lens L3 having a concave surface facingthe object and a positive lens L4 having a convex surface facing theimage, and a biconvex positive lens L5, which are disposed in order fromthe object. Because of this configuration, the imaging lens SL accordingto the second embodiment, of which angle of view exceeds 60°, and whichis compact and can implement excellent image forming performance, can becreated.

In the second embodiment having the above configuration, a conditionexpressed by the following expression (5)3.0<TL/Ymax<4.0  (5)is satisfied, where TL is the total length of the imaging lens (lengthon the optical axis from the first surface from the object to the imageplane in FIG. 19), and Ymax is the maximum image height.

The conditional expression (5) is a conditional expression to specify anappropriate total length for implementing downsizing and higherperformance. If the upper limit value of the conditional expression (5)is exceeded, the total length of the lens system increases, which isadvantageous for correcting aberrations, but looses the balance ofdownsizing and higher performance, and an increase in the total lengthof the lens system runs counter to the intent of the present invention,therefore is not preferable. If the lower limit value of the conditionalexpression (5) is not reached, on the other hand, this is advantageousfor downsizing, but the spherical aberration, coma aberration andcurvature of field generated in the imaging lens cannot be correctedsatisfactorily, which is not preferable.

To make the effect of the present invention certain, it is preferablethat the upper limit value of the conditional expression (5) is 3.95. Tomake the effect of the present invention more certain, it is preferablethat the upper limit value of the conditional expression (5) is 3.90.

To make the effect of the present invention certain, it is preferablethat the lower limit value of the conditional expression (5) is 3.10. Tomake the effect of the present invention more certain, it is preferablethat the lower limit value of the conditional expression (5) is 3.30.

In the second embodiment, it is preferable that a condition expressed bythe following expression (6)1.7<TL/Σd<2.2  (6)is satisfied, where TL is a total length of the imaging lens, and Σd isa length on the optical axis from the lens surface closest to the objectin the first lens group (first surface from the object in FIG. 19), andthe lens surface closest to the image in the second lens group (twelfthsurface from the object in FIG. 19).

The conditional expression (6) is a conditional expression to specify anappropriate total length for implementing downsizing and higherperformance. If the upper limit value of the conditional expression (6)is exceeded, the total length of the lens system increases, which isadvantageous for correcting aberrations, but looses the balance ofdownsizing and higher performance, and the increase in total length ofthe lens system runs counter to the intent of the present invention,therefore is not preferable. If the lower limit value of the conditionalexpression (6) is not reached, on the other hand, this is advantageousfor downsizing, but the spherical aberration, coma aberration andcurvature of field generated in the imaging lens cannot be correctedsatisfactorily, which is not preferable. This also makes it difficult toincrease back focus.

To make the effect of the present invention certain, it is preferablethat the upper limit value of the conditional expression (6) is 2.15. Tomake the effect of the present invention more certain, it is preferablethat the upper limit value of the conditional expression (6) is 2.10. Tomake the effect of the present invention even more certain, it ispreferable that the upper limit value of the conditional expression (6)is 2.05.

To make the effect of the present invention certain, it is preferablethat the lower limit value of the conditional expression (6) is 1.75. Tomake the effect of the present invention more certain, it is preferablethat the lower limit value of the conditional expression (6) is 1.80. Tomake the effect of the present invention even more certain, it ispreferable that the lower limit value of the conditional expression (6)is 1.85.

In the second embodiment, it is preferable that the first lens group G1further comprises a negative meniscus lens L1 having a convex surfacefacing the object, and a positive meniscus lens L2 having a convexsurface facing the object. Because of this configuration, in the imaginglens SL of the second embodiment, higher performance and downsizing canbe balanced satisfactorily, and the spherical aberration and curvatureof field generated in the first lens group G1 alone can be correctedsatisfactorily.

In the second embodiment, it is preferable that the first lens group G1includes at least one aspherical surface (second surface from the objectin FIG. 19). Because of this configuration, higher performance anddownsizing can be balanced, and the spherical aberration and curvatureof field can be corrected satisfactorily.

In the second embodiment, it is preferable that the second lens group G2further comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object. Because of thisconfiguration, curvature of field and coma aberration can be correctedsatisfactorily, and higher performance of the present imaging lens SLcan be implemented.

In the second embodiment, it is preferable that focus on a close objectis adjusted by moving the second lens group G2 toward the object.Because of this configuration, fluctuation of aberration upon focusadjustment can be suppressed, and interference of a lens or a mechanicalcomponent to support a lens can be prevented, since the feed pitch ofthe second lens group G2 toward the object upon focus adjustment is verysmall. It is possible to adjust focus on a close object using the firstlens group G1, but the feed pitch toward the object becomes very large,which causes a change in the total length of the lens. Along with thischange, such a mechanism as a drive system becomes complicated, anddownsizing becomes difficult. Also deterioration of the sphericalaberration and curvature of field increase, which is not preferable.

In the second embodiment, it is preferable that the second lens group G2includes at least one aspherical surface (twelfth surface from theobject in FIG. 19). Because of this configuration, fluctuation ofdistortion and curvature of field generated upon focusing can becorrected satisfactorily, and higher performance of the present imaginglens SL can be implemented.

In the second embodiment, in order to prevent failure of photography dueto an image blur caused by camera motion, it is possible that a blurdetection system for detecting the blur of the lens system and the drivemeans are combined in the lens system, and all or a part of one lensgroup, out of the lens group constituting the lens system, aredecentered as a shift lens group, and an image is shifted by driving theshift lens group by the drive means so as to correct the image blur(fluctuation of image plane position) caused by a blur of the lenssystem detected by the blur detection system, thereby the image blur canbe corrected. As mentioned above, the imaging lens SL of the secondembodiment can function as a vibration proof optical system.

The imaging lens SL according to the second embodiment comprises twolens groups, that is, the first lens group G1 and the second lens groupG2, but another lens group may be added between the lens groups, oranother lens group may be added adjacent to the image side of the firstlens group G1 or the object side of the second lens group G2.

In the imaging lens SL according to the second embodiment, it ispreferable that the distance from the image side lens surface to theimage plane (back focus) of the positive lens L5 disposed closest to theimage is about 10 to 30 mm in the shortest state. In the imaging lensSL, it is preferable that the image height is 5 to 12.5 mm, and morepreferably is 5 to 9.5 mm.

Examples of the Second Embodiment

Example 2-1 to Example 2-8 according to the second embodiment will nowbe described with reference to the drawings. FIG. 19, FIG. 21, FIG. 23,FIG. 25, FIG. 27, FIG. 29, FIG. 31 and FIG. 33 are cross-sectional viewsdepicting a configuration of the imaging lens SL (SL1 to SL8) accordingto each example, where the change of focusing state, from focusing oninfinity to focusing on a close object of the imaging lenses SL1 to SL8,that is, the state of movement of each lens group upon focusing, isshown by an arrow.

As described above, the imaging lens SL1 to SL8 according to eachexample comprises a first lens group G1 having a positive refractivepower, an aperture stop S, a second lens group G2 having a positiverefractive power, and a filter group FL which includes a low passfilter, infrared cut filter or the like, which are disposed in orderfrom an object. Upon focusing from the state of focusing on infinity tothe state of focusing on a close object, the first lens group G1 isfixed with respect to the image plane I, and the second lens group G2 ismoved with respect to the image plane I, so as to change the distancebetween the first lens group G1 and the second lens group G2. The imageplane I is formed on an unillustrated image sensing element, and thisimage sensing element is CCD or CMOS, for example.

Table 2-1 to Table 2-8 shown below are tables of each parameteraccording to Example 2-1 to Example 2-8. Description of the tables,which is the same as the tables of the first embodiment, is omitted. Inthe [conditional expression], values corresponding to the expressions(5) and (6) are shown.

Example 2-1

The imaging lens SL1 according to Example 2-1 will now be described withreference to FIG. 19, FIGS. 20A and 20B and Table 2-1. As FIG. 19 shows,in the imaging lens SL1 according to Example 2-1, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-1, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-1 shows a table on each parameter of Example 2-1. The surfacenumbers 1 to 18 in Table 2-1 correspond to the surfaces 1 to 18 in FIG.19. In Example 2-1, the second surface and the twelfth surface areaspherical.

TABLE 2-1 [Surface data] Surface number r d nd νd 1 12.5540 0.90 1.6779054.89 *2 5.1200 0.80 3 7.2279 1.90 1.88300 40.76 4 25.2952 0.80 5 0.00001.40 (Flare stop S1) 6 0.0000 (d6)  (Aperture stop S) 7 0.0000 1.00(Flare stop S2) 8 −5.1593 0.90 1.80810 22.76 9 −15.0968 2.65 1.7550052.32 10 −6.5278 0.20 11 25.0474 2.70 1.58913 61.16 *12 −19.8008 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.1200 κ = +0.9952 C4 = −3.5496E−04 C6 =−1.3835E−05 C8 = −6.4411E−08 C10 = −2.8213E−08 Twelfth surface r =−19.8008 κ = +5.2781 C4 = +2.1953E−04 C6 = −1.0580E−07 C8 = +2.9574E−08C10 = −2.6872E−10 [Various data] f = 14.26 FNO = 2.83 2ω = 62.12 Y =8.50 TL = 31.51 [Variable distance data] Infinity Close Object d6 1.85140.6000 d12 10.4286 11.6800 Bf 0.5058 0.5058 [Lens group data] Firstsurface Focal length First lens group 1 58.2236 Second lens group 714.9735 [Conditional expression] TL = 31.5058 Ymax = 8.5000 Σd = 15.1014Conditional expression (5) TL/Ymax = 3.7066 Conditional expression (6)TL/Σd = 2.0863

As the parameter table in Table 2-1 shows, the imaging lens SL1according to Example 2-1 satisfies the conditional expressions (5) and(6).

FIGS. 20A and 20B are graphs showing various aberrations of the imaginglens SL1 according to Example 2-1, where FIG. 20A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 20B are graphsshowing various aberrations upon focusing on a close object. In eachgraph showing aberrations, NA is a numerical aperture, FNO is an Fnumber, A is a half angle of view with respect to each image height, andHO is a height of an object. d indicates aberrations with respect to thed-line (wavelength: 587.6 nm), g indicates aberrations with respect tothe g-line (wavelength: 435.8 nm), C indicates aberrations with respectto the C-line (wavelength: 656.3 nm), and F indicates aberrations withrespect to the F-line (wavelength: 486.1 nm). Aberrations with nodescription indicate aberrations with respect to the d-line. In thegraph showing astigmatism, a solid line indicates a sagittal imagesurface, and a broken line indicates a meridional image surface.

The above description on the graphs showing aberrations is the same forother examples, therefore description thereof is omitted.

Also each graph showing aberrations show, according to the imaging lensSL1 of Example 2-1, various aberrations can be corrected satisfactorilyfrom a state of focusing on infinity to a state of focusing on a closeobject, and excellent imaging performance is Implemented.

Example 2-2

The imaging lens SL2 according to Example 2-2 will now be described withreference to FIG. 21, FIGS. 22A and 22B and Table 2-2. As FIG. 21 shows,in the imaging lens SL2 according to Example 2-2, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-2, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-2 shows a table on each parameter of Example 2-2. The surfacenumbers 1 to 18 in Table 2-2 correspond to the surfaces 1 to 18 in FIG.21. In Example 2-2, the second surface and the twelfth surface areaspherical.

TABLE 2-2 [Surface data] Surface number r d nd νd 1 11.8261 0.90 1.6779054.89 *2 5.0108 0.65 3 7.0263 1.85 1.88300 40.76 4 23.3567 0.70 5 0.00001.40 (Flare stop S1) 6 0.0000 (d6)  (Aperture stop S) 7 0.0000 1.00(Flare stop S2) 8 −5.0661 0.90 1.80810 22.76 9 −14.6310 2.70 1.7550052.32 10 −6.3977 0.20 11 23.5294 2.70 1.58913 61.16 *12 −21.4493 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.0108 κ = +0.1277 C4 = +4.8479E−04 C6 =+5.6078E−06 C8 = +1.1439E−07 C10 = +2.6889E−09 Twelfth surface r =−21.4493 κ = −5.6807 C4 = +6.6823E−05 C6 = −6.8560E−08 C8 = +2.3185E−08C10 = −3.6236E−10 [Various data] f = 14.26 FNO = 2.88 2ω = 62.12 Y =8.50 TL = 31.01 [Variable distance data] Infinity Close Object d6 1.85080.6000 d12 10.1792 11.4301 Bf 0.5070 0.5070 [Lens group data] Firstsurface Focal length First lens group 1 56.8827 Second lens group 714.7636 [Conditional expression] TL = 31.0070 Ymax = 8.5000 Σd = 14.8508Conditional expression (5) TL/Ymax = 3.6479 Conditional expression (6)TL/Σd = 2.0879

As the parameter table in Table 2-2 shows, the imaging lens SL2according to Example 2-2 satisfies the conditional expressions (5) and(6).

FIGS. 22A and 22B are graphs showing various aberrations of the imaginglens SL2 according to Example 2-2, where FIG. 22A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 22B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL2 ofExample 2-2, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Example 2-3

The imaging lens SL3 according to Example 2-3 will now be described withreference to FIG. 23, FIGS. 24A and 24B and Table 2-3. As FIG. 23 shows,in the imaging lens SL3 according to Example 2-3, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-3, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-3 shows a table on each parameter of Example 2-3. The surfacenumbers 1 to 18 in Table 2-3 correspond to the surfaces 1 to 18 in FIG.23. In Example 2-3, the second surface and the twelfth surface areaspherical.

TABLE 2-3 Surface number r d nd νd 1 12.6464 0.90 1.66910 55.42 *25.7001 0.75 3 7.7231 1.67 1.88300 40.76 4 24.6238 0.20 5 0.0000 1.40(Flare stop S1) 6 0.0000 (d6)  (Aperture stop S) 7 0.0000 1.50 (Flarestop S2) 8 −5.0699 0.90 1.80810 22.76 9 −18.5950 3.00 1.80400 46.57 10−7.0355 0.20 11 26.7580 3.12 1.61881 63.85 *12 −18.8179 (d12) 13 0.00001.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.14 16 0.00000.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Aspherical data]Second surface r = 5.7001 κ = +1.7002 C4 = −7.4793E−04 C6 = −3.1424E−05C8 = +2.0843E−07 C10 = −1.3010E−07 Twelfth surface r = −18.8179 κ =−7.0961 C4 = −3.0038E−05 C6 = +1.0404E−06 C8 = −1.2568E−09 C10 =−4.7030E−11 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y = 8.50 TL =32.01 [Variable distance data] Infinity Close Object d6 2.4197 1.1500d12 9.9683 11.2380 Bf 0.5123 0.5123 [Lens group data] First surfaceFocal length First lens group 1 48.8782 Second lens group 7 14.6742[Conditional expression] TL = 32.0123 Ymax = 8.5000 Σd = 16.0617Conditional expression (5) TL/Ymax = 3.7661 Conditional expression (6)TL/Σd = 1.9931

As the parameter table in Table 2-3 shows, the imaging lens SL3according to Example 2-3 satisfies the conditional expressions (5) and(6).

FIGS. 24A and 24B are graphs showing various aberrations of the imaginglens SL3 according to Example 2-3, where FIG. 24A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 24B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL3 ofExample 2-3, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Example 2-4

The imaging lens SL4 according to Example 2-4 will now be described withreference to FIG. 25, FIGS. 26A and 263 and Table 2-4. As FIG. 25 shows,in the imaging lens SL4 according to Example 2-4, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-4, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-4 shows a table on each parameter of Example 2-4. The surfacenumbers 1 to 18 in Table 2-4 correspond to the surfaces 1 to 18 in FIG.25. In Example 2-4, the second surface and the twelfth surface areaspherical.

TABLE 2-4 [Surface data] Surface number r d nd νd 1 9.9874 0.90 1.6889331.08 *2 5.0739 0.45 3 6.3837 1.76 1.85026 32.35 4 17.4312 0.30 5 0.00001.95 (Flare stop S1) 6 0.0000 0.45 (Aperture stop S) 7 0.0000 1.50(Flare stop S2) 8 −4.8003 0.90 1.80810 22.76 9 −18.5588 2.98 1.8160046.62 10 −6.7015 0.20 11 20.2148 2.86 1.66910 55.42 *12 −30.3443 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.0739 κ = −2.9635 C4 = +3.4708E−03 C6 =−1.4779E−04 C8 = +8.3851E−06 C10 = −2.3110E−07 Twelfth surface r =−30.3443 κ = −0.7304 C4 = +1.2477E−04 C6 = +4.7254E−07 C8 = +9.6784E−09C10 = −1.1595E−10 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y =8.50 TL = 30.00 [Variable distance data] Infinity Close Object d6 1.74730.4500 d12 8.4731 9.7704 Bf 0.4998 0.4998 [Lens group data] Firstsurface Focal length First lens group 1 39.8259 Second lens group 714.1972 [Conditional expression] TL = 29.9998 Ymax = 8.5000 Σd = 15.5569Conditional expression (5) TL/Ymax = 3.5294 Conditional expression (6)TL/Σd = 1.9284

As the parameter table in Table 2-4 shows, the imaging lens SL4according to Example 2-4 satisfies the conditional expressions (5) and(6).

FIGS. 26A and 26B are graphs showing various aberrations of the imaginglens SL4 according to Example 2-4, where FIG. 26A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 26B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL4 ofExample 2-4, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Example 2-5

The imaging lens SL5 according to Example 2-5 will now be described withreference to FIG. 27, FIGS. 28A and 28B and Table 2-5. As FIG. 27 shows,in the imaging lens SL5 according to Example 2-5, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-5, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-5 shows a table on each parameter of Example 2-5. The surfacenumbers 1 to 18 in Table 2-5 correspond to the surfaces 1 to 18 in FIG.27. In Example 2-5, the second surface and the twelfth surface areaspherical.

TABLE 2-5 [Surface data] Surface number r d nd νd 1 9.3520 0.90 1.6779054.89 *2 4.8208 0.45 3 5.9177 1.85 1.81600 46.62 4 15.9734 0.35 5 0.00001.95 (Flare stop S1) 6 0.0000 (d6)  (Aperture stop S) 7 0.0000 1.60(Flare stop S2) 8 −4.6847 0.90 1.80810 22.76 9 −18.5193 3.04 1.8160046.62 10 −6.7523 0.20 11 19.5054 3.10 1.66910 55.42 *12 −28.1863 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 4.8208 κ = −2.2502 C4 = +3.2855E−03 C6 =−1.1017E−04 C8 = +6.2421E−06 C10 = −1.6029E−07 Twelfth surface r =−28.1863 κ = +3.4908 C4 = +1.4959E−04 C6 = −3.4328E−07 C8 = +5.0300E−09C10 = −5.9841E−11 [Various data] f = 14.26 FNO = 2.92 2ω = 62.12 Y =8.50 TL = 30.00 [Variable distance data] Infinity Close Object d6 1.61520.3000 d12 8.0762 9.3915 Bf 0.4989 0.4989 [Lens group data] Firstsurface Focal length First lens group 1 36.9620 Second lens group 714.0056 [Conditional expression] TL = 29.9989 Ymax = 8.5000 Σd = 15.9538Conditional expression (5) TL/Ymax = 3.5293 Conditional expression (6)TL/Σd = 1.8804

As the parameter table in Table 2-5 shows, the imaging lens SL5according to Example 2-5 satisfies the conditional expressions (5) and(6).

FIGS. 28A and 28B are graphs showing various aberrations of the imaginglens SL5 according to Example 2-5, where FIG. 28A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 28B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL5 ofExample 2-5, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Example 2-6

The imaging lens SL6 according to Example 2-6 will now be described withreference to FIG. 29, FIGS. 30A and 30B and Table 2-6. As FIG. 29 shows,in the imaging lens SL6 according to Example 2-6, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-6, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-6 shows a table on each parameter of Example 2-6. The surfacenumbers 1 to 18 in Table 2-6 correspond to the surfaces 1 to 18 in FIG.29. In Example 2-6, the second surface and the twelfth surface areaspherical.

TABLE 2-6 [Surface data] Surface number r d nd νd 1 8.7469 0.90 1.6779054.89 *2 4.6799 0.45 3 5.8268 1.85 1.81600 46.62 4 14.7269 0.35 5 0.00001.95 (Flare stop S1) 6 0.0000 (d6)  (Aperture stop S) 7 0.0000 1.45(Flare stop S2) 8 −4.7008 0.90 1.80810 22.76 9 −19.5674 3.05 1.8160046.62 10 −6.8100 0.20 11 20.7908 3.10 1.66910 55.42 *12 −24.7647 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 4.6799 κ = −1.0342 C4 = +2.1291E−03 C6 =−2.5886E−05 C8 = +2.2070E−06 C10 = −5.3593E−08 Twelfth surface r =−24.7647 κ = −7.3551 C4 = +6.0709E−05 C6 = +1.2096E−08 C8 = +2.7737E−09C10 = −5.6169E−11 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y =8.50 TL = 30.00 [Variable distance data] Infinity Close Object d6 1.65750.3500 d12 8.1725 9.4800 Bf 0.4953 0.4953 [Lens group data] Firstsurface Focal length First lens group 1 37.8004 Second lens group 713.8767 [Conditional expression] TL = 29.9953 Ymax = 8.5000 Σd = 15.8575Conditional expression (5) TL/Ymax = 3.5289 Conditional expression (6)TL/Σd = 1.8916

As the parameter table in Table 2-6 shows, the imaging lens SL6according to Example 2-6 satisfies the conditional expressions (5) and(6).

FIGS. 30A and 30B are graphs showing various aberrations of the imaginglens SL6 according to Example 2-6, where FIG. 30A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 30B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL6 ofExample 2-6, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Example 2-7

The imaging lens SL7 according to Example 2-7 will now be described withreference to FIG. 31, FIGS. 32A and 32B and Table 2-7. As FIG. 31 shows,in the imaging lens SL7 according to Example 2-7, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-7, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-7 shows a table on each parameter of Example 2-7. The surfacenumbers 1 to 18 in Table 2-7 correspond to the surfaces 1 to 18 in FIG.31. In Example 2-7, the second surface and the twelfth surface areaspherical.

TABLE 2-7 [Surface data] Surface number r d nd νd 1 14.0147 0.90 1.6779054.89 *2 5.4694 0.90 3 7.6437 1.75 1.88300 40.76 4 30.8895 0.25 5 0.00001.60 (Flare stop S1) 6 0.0000 (d6)  (Aperture stop S) 7 0.0000 1.25(Flare stop S2) 8 −5.1623 0.95 1.80810 22.76 9 −14.4718 2.75 1.7550052.32 10 −6.7218 0.20 11 26.5149 2.85 1.59201 67.02 *12 −18.8905 (d12)13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.1416 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Asphericaldata] Second surface r = 5.4694 κ = +1.4173 C4 = −6.4702E−04 C6 =−2.1283E−05 C8 = −4.5161E−07 C10 = −6.2922E−08 Twelfth surface r =−18.8905 κ = +5.5850 C4 = +2.2637E−04 C6 = +8.5167E−07 C8 = +1.1963E−08C10 = +1.5290E−10 [Various data] f = 14.26 FNO = 2.83 2ω = 62.07 Y =8.50 TL = 32.01 [Variable distance data] Infinity Close Object d6 2.06760.8000 d12 10.5324 11.8300 Bf 0.5145 0.5145 [Lens group data] Firstsurface Focal length First lens group 1 51.9495 Second lens group 715.2959 [Conditional expression] TL = 32.0145 Ymax = 8.5000 Σd = 15.4676Conditional expression (5) TL/Ymax = 3.7664 Conditional expression (6)TL/Σd = 2.0698

As the parameter table in Table 2-7 shows, the imaging lens SL7according to Example 2-7 satisfies the conditional expressions (5) and(6).

FIGS. 32A and 32B are graphs showing various aberrations of the imaginglens SL7 according to Example 2-7, where FIG. 32A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 32B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL7 ofExample 2-7, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Example 2-8

The imaging lens SL8 according to Example 2-8 will now be described withreference to FIG. 33, FIGS. 34A and 34B and Table 2-8. As FIG. 33 shows,in the imaging lens SL8 according to Example 2-8, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 2-8, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 2-8 shows a table on each parameter of Example 2-8. The surfacenumbers 1 to 18 in Table 2-8 correspond to the surfaces 1 to 18 in FIG.33. In Example 2-8, the second surface and the twelfth surface areaspherical.

TABLE 2-8 [Surface data] Surface number r d nd νd  1 14.0077 1.301.67790 54.89 *2 5.3933 0.60  3 7.5715 1.95 1.88300 40.76  4 28.36630.25  5 0.0000 1.75 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.25 (Flare stop S2)  8 −5.2273 0.98 1.80810 22.76  9 −15.14712.88 1.75500 52.32 10 −6.7013 0.20 11 23.0044 2.94 1.59201 67.02 *12 −20.7345 8.96 13 0.0000 0.50 1.51633 64.14 14 0.0000 4.60 15 0.0000 1.871.51633 64.14 16 0.0000 0.30 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf)[Aspherical data] Second surface r = 5.3933 κ = +1.7327 C4 = −9.1467E−04C6 = −4.4123E−05 C8 = +8.7126E−07 C10 = −2.7436E−07 Twelfth surface r =−20.7345 κ = −19.0000 C4 = −1.4487E−04 C6 = +4.4684E−06 C8 = −5.5750E−08C10 = +3.1253E−10 [Various data] f = 14.26 FNO = 2.92 2ω = 62.50 Y =8.50 TL = 32.36 [Variable distance data] Infinity Close Object d6 2.03760.8000 d12 7.7203 8.9579 Bf 0.5348 0.5348 [Lens group data] Firstsurface Focal length First lens group 1 51.9495 Second lens group 714.3554 [Conditional expression] TL = 32.3620 Ymax = 8.5000 Σd = 16.1369Conditional expression (5) TL/Ymax = 3.8073 Conditional expression (6)TL/Σd = 2.0055

As the parameter table in Table 2-8 shows, the imaging lens SL8according to Example 2-8 satisfies the conditional expressions (5) and(6).

FIGS. 34A and 34B are graphs showing various aberrations of the imaginglens SL8 according to Example 2-8, where FIG. 34A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 34B are graphsshowing various aberrations upon focusing on a close object. Also eachgraph showing aberrations show, according to the imaging lens SL8 ofExample 2-8, various aberrations can be corrected satisfactorily from astate of focusing on infinity to a state of focusing on a close object,and excellent imaging performance is implemented.

Third Embodiment

A third embodiment of the imaging lens according to the presentinvention will now be described. The third embodiment includes examples(Example 3-1 to Example 3-8) herein below.

The imaging lens SL according to the third embodiment includesconfigurations of Example 3-1 to Example 3-8 shown in FIG. 35, FIG. 37,FIG. 39, FIG. 41, FIG. 43, FIG. 45, FIG. 47 and FIG. 49, but isdescribed using the configuration in FIG. 35 as an example. This imaginglens SL comprises an object side lens group G1 having a positiverefractive power and an image side lens group G2 having a positiverefractive power with an air distance from the object side lens groupG1, which are disposed in order from the object, wherein the image sidelens group G2 further comprises a cemented lens L34 of a negative lensL3 having a concave surface facing the object and a positive lens L4having a convex surface facing the image, and a biconvex positive lensL5, which are disposed in order from the object, and all or a part ofthe image side lens group G2 can be shifted in a direction substantiallyperpendicular to the optical axis. Because of this configuration, theimaging lens SL according to the third embodiment, in which an image onthe image plane can be shifted, an angle of view exceeds 60°, and acompact and excellent image forming performance can be implemented, canbe created.

In the third embodiment, it is preferable that a condition expressed bythe following expression (7)0.80<f/fS<1.10  (7)is satisfied, where f is a focal length of the imaging lens, and fS(focal length f2 of the image side lens group G2 in the thirdembodiment) is a focal length of the shift lens group (image side lensgroup G2 in FIG. 35).

The conditional expression (7) is a conditional expression to specifythe focal length fS of the shift lens group. If the upper limit value ofthe conditional expression (7) is exceeded, the refractive power of theshift lens group increases, and the spherical aberrations generated inthe shift lens group alone increase, which is not preferable. If thelower limit value of the conditional expression (7) is not reached, onthe other hand, the refractive power of the shift lens group becomesweak, and [the lens] is no longer a focal, so the change of curvature offield when the lens is shifted increases, which is not preferable.

To make the effect of the present invention certain, it is preferablethat the upper limit value of the conditional expression (7) is 1.07. Tomake the effect of the present invention more certain, it is preferablethat the upper limit value of the conditional expression (7) is 1.05.

To make the effect of the present invention more certain, it ispreferable that the lower limit value of the conditional expression (7)is 0.83. To make the effect of the present invention more certain, it ispreferable that the lower limit value of the conditional expression (7)is 0.86. To make the effect of the present invention even more certain,it is preferable that the lower limit value of the conditionalexpression (7) is 0.90.

In the third embodiment, it is preferable that the condition expressedby the following expression (8)0.13<f2/f1<0.47  (8)is satisfied, where f1 is a focal length of the object side lens groupG1 and f2 is a focal length of the image side lens group G2.

The conditional expression (8) is a conditional expression to specify anoptimum range of the focal length ratio of the object side lens group G1and the image side lens group G2. If the upper limit value of theconditional expression (8) is exceeded, the refractive power of theobject side lens group G1 becomes relatively high, which makes itdifficult to correct the spherical aberration and coma aberrationgenerated in the object side lens group G1 alone. Also the refractivepower of the image side lens group G2 becomes relatively weak, and thecurvature of field cannot be corrected satisfactorily, which is notpreferable. If the lower limit value of the conditional expression (8)is not reached, on the other hand, the refractive power of the objectside lens group G1 becomes relatively weak, and correction of thespherical aberration becomes insufficient, which is not preferable. Alsothe refractive power of the image side lens G2 becomes relativelystrong, which increases the coma aberration generated in the image sidelens group G2, and makes it impossible to achieve the object of thepresent invention, that is, implementing an excellent opticalperformance.

To make the effect of the present invention certain, it is preferablethat the upper limit value of the conditional expression (8) is 0.45. Tomake the effect of the present invention more certain, it is preferablethat the upper limit value of the conditional expression (8) is 0.43. Tomake the effect of the present invention even more certain, it ispreferable that the upper limit value of the conditional expression (8)is 0.40.

To make the effect of the present invention certain, it is preferablethat the lower limit value of the conditional expression (8) is 0.15. Tomake the effect of the present invention more certain, it is preferablethat the lower limit value of the conditional expression (8) is 0.17. Tomake the effect of the present invention even more certain, it ispreferable that the lower limit value of the conditional expression (8)is 0.19.

In the third embodiment, it is preferable that the cemented lens L34 ofthe image side lens group G2 further comprises a negative meniscus lensL3 having a concave surface facing the object and a positive meniscuslens L4 having a convex surface facing the image. Because of thisconfiguration, the curvature of field can be corrected satisfactorily,and higher performance of the imaging lens SL can be implemented.

In the third embodiment, it is preferable that the biconvex positivelens component L5 of the image side lens group G2 has at least oneaspherical surface (twelfth surface from the object in FIG. 35). Becauseof this configuration, fluctuation of distortion and curvature of fieldgenerated upon focusing can be corrected satisfactorily, even if thefocusing lens group includes the positive lens component L5, and higherperformance of the imaging lens SL can be implemented.

In the third embodiment, it is preferable that an aperture stop S isdisposed between the object side lens group G1 and the image side lensgroup G2. Because of this configuration, the refractive power isdistributed in a more symmetric way, that is, the object side lens groupG1 having a positive refractive power, the aperture stop S, and theimage side lens group G2 having a positive refractive power, aredisposed in order from the object, so that the curvature of field anddistortion can be corrected satisfactorily.

In the third embodiment, it is preferable that focus on a close objectis adjusted by moving the image side lens group G2 toward the object.Because of this configuration, fluctuation of aberration upon focusadjustment can be suppressed, and interference of a lens or a mechanicalcomponent to support a lens can be prevented, since a feed pitch of theimage side lens group G2 toward the object upon focus adjustment is verysmall. It is possible to adjust focus on a close object using the objectside lens group G1, but a feed pitch toward the object becomes verylarge, which causes a change in the total length of the lens. Along withthis change, such a mechanism as a drive system becomes complicated, anddownsizing becomes difficult. Also deterioration of the sphericalaberration and curvature of field increase, which is not preferable.

The imaging lens SL according to the third embodiment comprises two lensgroups, that is, the object side lens group G1 and the image side lensgroup G2, but another lens group may be added between the lens groups oranother lens group may be added adjacent to the image side of the objectside lens group G1 or the object side of the image side lens group G2.

In the imaging lens SL according to the third embodiment, it ispreferable that the distance from the image side lens surface to theimage plane (back focus) of the positive lens disposed closest to theimage is about 10 to 30 mm in the shortest state. In the imaging lensSL, it is preferable that the image height is 5 to 12.5 mm, and morepreferably 5 to 9.5 mm.

Examples of the Third Embodiment

Example 3-1 to Example 3-8 according to the third embodiment will now bedescribed with reference to the drawings. FIG. 35, FIG. 37, FIG. 39,FIG. 41, FIG. 43, FIG. 45, FIG. 47 and FIG. 49 are cross-sectional viewsdepicting a configuration of the imaging lens SL (SL1 to SL8) accordingto each example, where the change of focusing state, from focusing oninfinity to focusing on a close object of the imaging lenses SL1 to SL8,that is, the state of movement of each lens group upon focusing, isshown by an arrow.

As described above, the imaging lens SL1 to SL8 according to eachexample comprises the object side lens group G1 having a positiverefractive power, the aperture stop S, the image side lens group G2having a positive refractive power, and the filter group FL whichincludes a low pass filter, infrared cut filter or the like, which aredisposed in order from the object. Upon focusing from a state offocusing on infinity to the state of focusing on a close object, theobject side lens group G1 is fixed with respect to the image plane I,and the image side lens group G2 is moved with respect to the imageplane I, so as to change the distance between the object side lens groupG1 and the image side lens group G2. The image plane I is formed on anunillustrated image sensing element, and this image sensing element isCCD or CMOS, for example.

Table 3-1 to Table 3-8 shown below are tables of parameters according toExample 3-1 to Example 3-8. Description on the tables, which is the sameas the table of the first embodiment, is omitted. In [conditionalexpression], values corresponding to the conditional expressions (7) and(8) are shown.

Example 3-1

The imaging lens SL1 according to Example 3-1 will now be described withreference to FIG. 35, FIGS. 36A and 36B and Table 3-1. As FIG. 35 shows,in the imaging lens SL1 according to Example 3-1, the object side lensG1 comprises a negative meniscus lens L1 having a convex surface facingthe object and a positive meniscus lens L2 having a convex surfacefacing the object, which are disposed in order from the object. Theimage side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-1, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-1, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-1 shows a table on each parameter of Example 3-1. The surfacenumbers 1 to 18 in Table 3-1 correspond to the surfaces 1 to 18 in FIG.35. In Example 3-1, the second surface and the twelfth surface areaspherical.

TABLE 3-1 [Surface data] Surface number r d nd νd  1 12.5540 0.901.67790 54.89 *2 5.1200 0.80  3 7.2279 1.90 1.88300 40.76  4 25.29520.80  5 0.0000 1.40 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.00 (Flare stop S2)  8 −5.1593 0.90 1.80810 22.76  9 −15.09682.65 1.75500 52.32 10 −6.5278 0.20 11 25.0474 2.70 1.58913 61.16 *12 −19.8008 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.1200 κ = +0.9952 C4 =−3.5496E−04 C6 = −1.3835E−05 C8 = −6.4411E−08 C10 = −2.8213E−08 Twelfthsurface r = −19.8008 κ = +5.2781 C4 = +2.1953E−04 C6 = −1.0580E−07 C8 =+2.9574E−08 C10 = −2.6872E−10 [Various data] f = 14.26 FNO = 2.83 2ω =62.12 Y = 8.50 TL = 31.51 [Variable distance data] Infinity Close Objectd6 1.8514 0.6000 d12 10.4286 11.6800 Bf 0.5058 0.5058 [Lens group data]First surface Focal length Object side lens group 1 58.2236 Image sidelens group 7 14.9735 [Conditional expression] f = 14.2560 f1 = 58.2236fS(=f2) = 14.9765 Conditional expression (7) f/fS = 0.9521 Conditionalexpression (8) f2/f1 = 0.2572

As the parameter table in Table 3-1 shows, the imaging lens SL accordingto Example 3-1 satisfies the conditional expressions (7) and (8).

FIGS. 36A and 36B are graphs showing various aberrations of the imaginglens SL1 according to Example 3-1, where FIG. 36A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 363 are graphsshowing coma aberration during lens shift. In each graph showingaberrations, all data is shown with respect to the d-line (wavelength:587.6 nm), and FNO is an F number, and A is a half angle of view withrespect to each image height respectively. In the graph showingastigmatism, a solid line indicates a sagittal image surface, and abroken line indicates a meridional image surface. The above descriptionon the graphs showing aberrations is the same for other examples,therefore description thereof is omitted.

As each graph showing aberrations shows, in the imaging lens SLaccording to Example 3-1, various aberrations are correctedsatisfactorily during lens shift, and excellent image formingperformance is implemented.

Example 3-2

The imaging lens SL2 according to Example 3-2 will now be described withreference to FIG. 37 and FIGS. 38A and 38B and Table 3-2. As FIG. 37shows, in the imaging lens SL2 according to Example 3-2, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-2, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-2, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-2 shows a table on each parameter of Example 3-2. The surfacenumbers 1 to 18 in Table 3-2 correspond to the surfaces 1 to 18 in FIG.37. In Example 3-2, the second surface and the twelfth surface areaspherical.

TABLE 3-2 [Surface data] Surface number r d nd νd  1 11.8261 0.901.67790 54.89 *2 5.0108 0.65  3 7.0263 1.85 1.88300 40.76  4 23.35670.70  5 0.0000 1.40 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.00 (Flare stop S2)  8 −5.0661 0.90 1.80810 22.76  9 −14.63102.70 1.75500 52.32 10 −6.3977 0.20 11 23.5294 2.70 1.58913 61.16 *12 −21.4493 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.0108 κ = +0.1277 C4 =+4.8479E−04 C6 = +5.6078E−06 C8 = +1.1439E−07 C10 = +2.6889E−09 Twelfthsurface r = −21.4493 κ = −5.6807 C4 = +6.6823E−05 C6 = −6.8560E−08 C8 =+2.3185E−08 C10 = −3.6236E−10 [Various data] f = 14.26 FNO = 2.88 2ω =62.12 Y = 8.50 TL = 31.01 [Variable distance data] Infinity Close Objectd6 1.8508 0.6000 d12 10.1792 11.4301 Bf 0.5070 0.5070 [Lens group data]First surface Focal length Object side lens group 1 56.8827 Image sidelens group 7 14.7636 [Conditional expression] f = 14.2560 f1 = 56.8827fS(=f2) = 14.7636 Conditional expression (7) f/fS = 0.9656 Conditionalexpression (8) f2/f1 = 0.2595

As the parameter table in Table 3-2 shows, the imaging lens SL2according to Example 3-2 satisfies the conditional expressions (7) and(8).

FIGS. 38A and 38B are graphs showing various aberrations of the imaginglens SL2 according to Example 3-2, where FIG. 38A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 38B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL2 according to Example 3-2,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Example 3-3

The imaging lens SL3 according to Example 3-3 will now be described withreference to FIG. 39 and FIGS. 40A and 40B and Table 3-3. As FIG. 39shows, in the imaging lens SL3 according to Example 3-3, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-3, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-3, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-3 shows a table on each parameter of Example 3-3. The surfacenumbers 1 to 18 in Table 3-3 correspond to the surfaces 1 to 18 in FIG.39. In Example 3-3, the second surface and the twelfth surface areaspherical.

TABLE 3-3 [Surface data] Surface number r d nd νd  1 12.6464 0.901.66910 55.42 *2 5.7001 0.75  3 7.7231 1.67 1.88300 40.76  4 24.62380.20  5 0.0000 1.40 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.50 (Flare stop S2)  8 −5.0699 0.90 1.80810 22.76  9 −18.59503.00 1.80400 46.57 10 −7.0355 0.20 11 26.7580 3.12 1.61881 63.85 *12 −18.8179 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.7001 κ = +1.7002 C4 =−7.4793E−04 C6 = −3.1424E−05 C8 = +2.0843E−07 C10 = −1.3010E−07 Twelfthsurface r = −18.8179 κ = −7.0961 C4 = −3.0038E−05 C6 = +1.0404E−06 C8 =−1.2568E−09 C10 = −4.7030E−11 [Various data] f = 14.26 FNO = 2.91 2ω =62.12 Y = 8.50 TL = 32.01 [Variable distance data] Infinity Close Objectd6 2.4197 1.1500 d12 9.9683 11.2380 Bf 0.5123 0.5123 [Lens group data]First surface Focal length Object side lens group 1 48.8782 Image sidelens group 7 14.6742 [Conditional expression] f = 14.2560 f1 = 48.8782fS(=f2) = 14.6742 Conditional expression (7) f/fS = 0.9715 Conditionalexpression (8) f2/f1 = 0.3002

As the parameter table in Table 3-3 shows, the imaging lens SL3according to Example 3-3 satisfies the conditional expressions (7) and(8).

FIGS. 40A and 40B are graphs showing various aberrations of the imaginglens SL3 according to Example 3-3, where FIG. 40A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 40B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL3 according to Example 3-3,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Example 3-4

The imaging lens SL4 according to Example 3-4 will now be described withreference to FIG. 41 and FIGS. 42A and 42B and Table 3-4. As FIG. 41shows, in the imaging lens SL4 according to Example 3-4, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-4, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-4, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-4 shows a table on each parameter of Example 3-4. The surfacenumbers 1 to 18 in Table 3-4 correspond to the surfaces 1 to 18 in FIG.41. In Example 3-4, the second surface and the twelfth surface areaspherical.

TABLE 3-4 [Surface data] Surface number r d nd νd  1 9.9874 0.90 1.6889331.08 *2 5.0739 0.45  3 6.3837 1.76 1.85026 32.35  4 17.4312 0.30  50.0000 1.95 (Flare stop S1)  6 0.0000 0.45 (Aperture stop S)  7 0.00001.50 (Flare stop S2)  8 −4.8003 0.90 1.80810 22.76  9 −18.5588 2.981.81600 46.62 10 −6.7015 0.20 11 20.2148 2.86 1.66910 55.42 *12 −30.3443 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.0739 κ = −2.9635 C4 =+3.4708E−03 C6 = −1.4779E−04 C8 = +8.3851E−06 C10 = −2.3110E−07 Twelfthsurface r = −30.3443 κ = −0.7304 C4 = +1.2477E−04 C6 = +4.7254E−07 C8 =+9.6784E−09 C10 = −1.1595E−10 [Various data] f = 14.26 FNO = 2.91 2ω =62.12 Y = 8.50 TL = 30.00 [Variable distance data] Infinity Close Objectd6 1.7473 0.4500 d12 8.4731 9.7704 Bf 0.4998 0.4998 [Lens group data]First surface Focal length Object side lens group 1 39.8259 Image sidelens group 7 14.1972 [Conditional expression] f = 14.2560 f1 = 39.8259fS(=f2) = 14.1972 Conditional expression (7) f/fS = 1.0041 Conditionalexpression (8) f2/f1 = 0.3565

As the parameter table in Table 3-4 shows, the imaging lens SL4according to Example 3-4 satisfies the conditional expressions (7) and(8).

FIGS. 42A and 42B are graphs showing various aberrations of the imaginglens SL4 according to Example 3-4, where FIG. 42A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 42B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL4 according to Example 3-4,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Example 3-5

The imaging lens SL5 according to Example 3-5 will now be described withreference to FIG. 43 and FIGS. 44A and 44B and Table 3-5. As FIG. 43shows, in the imaging lens SL5 according to Example 3-5, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-5, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-5, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-5 shows a table on each parameter of Example 3-5. The surfacenumbers 1 to 18 in Table 3-5 correspond to the surfaces 1 to 18 in FIG.43. In Example 3-5, the second surface and the twelfth surface areaspherical.

TABLE 3-5 Surface number r d nd νd  1 9.3520 0.90 1.67790 54.89 *24.8208 0.45  3 5.9177 1.85 1.81600 46.62  4 15.9734 0.35  5 0.0000 1.95(Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  7 0.0000 1.60 (Flarestop S2)  8 −4.6847 0.90 1.80810 22.76  9 −18.5193 3.04 1.81600 46.62 10−6.7523 0.20 11 19.5054 3.10 1.66910 55.42 *12  −28.1863 (d12) 13 0.00001.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.14 16 0.00000.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Aspherical data]Second surface r = 4.8208 κ = −2.2502 C4 = +3.2855E−03 C6 = −1.1017E−04C8 = +6.2421E−06 C10 = −1.6029E−07 Twelfth surface r = −28.1863 κ =+3.4908 C4 = +1.4959E−04 C6 = −3.4328E−07 C8 = +5.0300E−09 C10 =−5.9841E−11 [Various data] f = 14.26 FNO = 2.92 2ω = 62.12 Y = 8.50 TL =30.00 [Variable distance data] Infinity Close Object d6 1.6152 0.3000d12 8.0762 9.3915 Bf 0.4989 0.4989 [Lens group data] First surface Focallength Object side lens group 1 36.9620 Image side lens group 7 14.0056[Conditional expression] f = 14.2560 f1 = 36.9620 fS(=f2) = 14.0056Conditional expression (7) f/fS = 1.0179 Conditional expression (8)f2/f1 = 0.3789

As the parameter table in Table 3-5 shows, the imaging lens SL5according to Example 3-5 satisfies the conditional expressions (7) and(8).

FIGS. 44A and 44B are graphs showing various aberrations of the imaginglens SL5 according to Example 3-5, where FIG. 44A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 44B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL5 according to Example 3-5,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Example 3-6

The imaging lens SL6 according to Example 3-6 will now be described withreference to FIG. 45 and FIGS. 46A and 46B and Table 3-6. As FIG. 45shows, in the imaging lens SL6 according to Example 3-6, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-6, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-6, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-6 shows a table on each parameter of Example 3-6. The surfacenumbers 1 to 18 in Table 3-6 correspond to the surfaces 1 to 18 in FIG.45. In Example 3-6, the second surface and the twelfth surface areaspherical.

TABLE 3-6 [Surface data] Surface number r d nd νd  1 8.7469 0.90 1.6779054.89 *2 4.6799 0.45  3 5.8268 1.85 1.81600 46.62  4 14.7269 0.35  50.0000 1.95 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  7 0.00001.45 (Flare stop S2)  8 −4.7008 0.90 1.80810 22.76  9 −19.5674 3.051.81600 46.62 10 −6.8100 0.20 11 20.7908 3.10 1.66910 55.42 *12 −24.7647 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 4.6799 κ = −1.0342 C4 =+2.1291E−03 C6 = −2.5886E−05 C8 = +2.2070E−06 C10 = −5.3593E−08 Twelfthsurface r = −24.7647 κ = −7.3551 C4 = +6.0709E−05 C6 = +1.2096E−08 C8 =+2.7737E−09 C10 = −5.6169E−11 [Various data] f = 14.26 FNO = 2.91 2ω =62.12 Y = 8.50 TL = 30.00 [Variable distance data] Infinity Close Objectd6 1.6575 0.3500 d12 8.1725 9.4800 Bf 0.4953 0.4953 [Lens group data]First surface Focal length Object side lens group 1 37.8004 Image sidelens group 7 13.8767 [Conditional expression] f = 14.2560 f1 = 37.8004fS(=f2) = 13.8767 Conditional expression (7) f/fS = 1.0273 Conditionalexpression (8) f2/f1 = 0.3671

As the parameter table in Table 3-6 shows, the imaging lens SL6according to Example 3-6 satisfies the conditional expressions (7) and(8).

FIGS. 46A and 46B are graphs showing various aberrations of the imaginglens SL6 according to Example 3-6, where FIG. 46A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 46B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL6 according to Example 3-6,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Example 3-7

The imaging lens SL7 according to Example 3-7 will now be described withreference to FIG. 47 and FIGS. 48A and 48B and Table 3-7. As FIG. 47shows, in the imaging lens SL7 according to Example 3-7, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-7, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-7, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-7 shows a table on each parameter of Example 3-7. The surfacenumbers 1 to 18 in Table 3-7 correspond to the surfaces 1 to 18 in FIG.47. In Example 3-7, the second surface and the twelfth surface areaspherical.

TABLE 3-7 [Surface data] Surface number r d nd νd  1 14.0147 0.901.67790 54.89 *2 5.4694 0.90  3 7.6437 1.75 1.88300 40.76  4 30.88950.25  5 0.0000 1.60 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.25 (Flare stop S2)  8 −5.1623 0.95 1.80810 22.76  9 −14.47182.75 1.75500 52.32 10 −6.7218 0.20 11 26.5149 2.85 1.59201 67.02 *12 −18.8905 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.4694 κ = +1.4173 C4 =−6.4702E−04 C6 = −2.1283E−05 C8 = −4.5161E−07 C10 = −6.2922E−08 Twelfthsurface r = −18.8905 κ = +5.5850 C4 = +2.2637E−04 C6 = +8.5167E−07 C8 =+1.1963E−08 C10 = +1.5290E−10 [Various data] f = 14.26 FNO = 2.83 2ω =62.07 Y = 8.50 TL = 32.01 [Variable distance data] Infinity Close Objectd6 2.0676 0.8000 d12 10.5324 11.8300 Bf 0.5145 0.5145 [Lens group data]First surface Focal length Object side lens group 1 51.9495 Image sidelens group 7 15.2959 [Conditional expression] f = 14.2560 f1 = 51.9495fS(=f2) = 15.2959 Conditional expression (7) f/fS = 0.9320 Conditionalexpression (8) f2/f1 = 0.2944

As the parameter table in Table 3-7 shows, the imaging lens SL7according to Example 3-7 satisfies the conditional expressions (7) and(8).

FIGS. 48A and 48B are graphs showing various aberrations of the imaginglens SL7 according to Example 3-7, where FIG. 48A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 48B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL7 according to Example 3-7,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Example 3-8

The imaging lens SL8 according to Example 3-8 will now be described withreference to FIG. 49 and FIGS. 50A and 50B and Table 3-8. As FIG. 49shows, in the imaging lens SL8 according to Example 3-8, the object sidelens G1 comprises a negative meniscus lens L1 having a convex surfacefacing the object and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.The image side lens group G2 comprises a cemented lens L34 of a negativemeniscus lens L3 having a concave surface facing the object and apositive meniscus lens L4 having a convex surface facing the image side,and a biconvex positive lens L5, which are disposed in order from theobject.

An aperture stop S is disposed between the object side lens group G1 andthe image side lens group G2, and is fixed with respect to the objectside lens group G1 or image plane I upon focusing from infinity to aclose object. Also a flare stop FS1 and flare stop FS2 are disposed atpre-positions and post positions of the aperture stop S.

In Example 3-8, an axial air distance d6 between the object side lensgroup G1 and the image side lens group G2, and the axial air distanced12 between the image side lens group G2 and the filter group FL, changeupon focusing.

Also in Example 3-8, the image side lens group G2 can be shifted in adirection substantially perpendicular to the optical axis as a shiftlens group.

Table 3-8 shows a table on each parameter of Example 3-8. The surfacenumbers 1 to 18 in Table 3-8 correspond to the surfaces 1 to 18 in FIG.49. In Example 3-8, the second surface and the twelfth surface areaspherical.

TABLE 3-8 [Surface data] Surface number r d nd νd  1 14.0077 1.301.67790 54.89 *2 5.3933 0.60  3 7.5715 1.95 1.88300 40.76  4 28.36630.25  5 0.0000 1.75 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.25 (Flare stop S2)  8 −5.2273 0.98 1.80810 22.76  9 −15.14712.88 1.75500 52.32 10 −6.7013 0.20 11 23.0044 2.94 1.59201 67.02 *12 −20.7345 8.96 13 0.0000 0.50 1.51633 64.14 14 0.0000 4.60 15 0.0000 1.871.51633 64.14 16 0.0000 0.30 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf)[Aspherical data] Second surface r = 5.3933 κ = +1.7327 C4 = −9.1467E−04C6 = −4.4123E−05 C8 = +8.7126E−07 C10 = −2.7436E−07 Twelfth surface r =−20.7345 κ = −19.0000 C4 = −1.4487E−04 C6 = +4.4684E−06 C8 = −5.5750E−08C10 = +3.1253E−10 [Various data] f = 14.26 FNO = 2.92 2ω = 62.50 Y =8.50 TL = 32.36 [Variable distance data] Infinity Close Object d6 2.03760.8000 d12 7.7203 8.9579 Bf 0.5348 0.5348 [Lens group data] Firstsurface Focal length Object side lens group 1 51.9495 Image side lensgroup 7 14.3554 [Conditional expression] f = 14.2560 f1 = 67.2632fS(=f2) = 14.3554 Conditional expression (7) f/fS = 0.9931 Conditionalexpression (8) f2/f1 = 0.2134

As the parameter table in Table 3-8 shows, the imaging lens SL8according to Example 3-8 satisfies the conditional expressions (7) and(8).

FIGS. 50A and 50B are graphs showing various aberrations of the imaginglens SL8 according to Example 3-8, where FIG. 50A are graphs showingvarious aberrations upon focusing on infinity, and FIG. 50B are graphsshowing coma aberration during lens shift. As each graph showingaberrations shows, in the imaging lens SL8 according to Example 3-8,various aberrations are corrected satisfactorily during lens shift, andexcellent image forming performance is implemented.

Fourth Embodiment

A fourth embodiment of the imaging lens according to the presentinvention will now be described. The fourth embodiment includes examples(Example 4-1 to Example 4-8) herein below.

The imaging lens SL according to the fourth embodiment includesconfigurations of Example 4-1 to Example 4-8 shown in FIG. 51, FIG. 53,FIG. 55, FIG. 57, FIG. 59, FIG. 61, FIG. 63 and FIG. 65, but isdescribed using the configuration in FIG. 51 as an example. As FIG. 51shows, this imaging lens SL comprises a first lens group G1 having apositive refractive power, an aperture stop S and a second lens group G2having a positive refractive power, which are disposed in order from anobject, where the first lens group G1 further comprises a negative lenscomponent L1 and a positive lens component L2, which are disposed inorder from the object, and the second lens group G2 further comprises acemented lens component L34 of a negative lens L3 and a positive lensL4, and a positive lens component L5, which are disposed in order fromthe object. Because of this configuration, the imaging lens SL accordingto the fourth embodiment, of which angle of view exceeds 60° and whichis compact and can implement excellent image forming performance, can becreated.

In the fourth embodiment having the above configuration, conditions ofthe following expressions (9) and (10)nd5<1.67  (9)νd5>50.0  (10)are satisfied, where nd 5 is a refractive index of the second positivelens component L5 of the second lens group G2 with respect to thed-line, and νd5 is an Abbe number of the second positive lens componentL5 of the second lens group G2 with respect to the d-line.

The conditional expressions (9) and (10) are conditions to minimizedeterioration of lateral chromatic aberration. If the conditionalexpressions (9) and (10) are not satisfied, fluctuation of the lateralchromatic aberration upon focusing increases, and photographicperformance at close distance deteriorates, which is not preferable.

To make the effect of the fourth embodiment certain, it is preferablethat the lower limit value of the conditional expression (10) is 51.50.To make the effect of the fourth embodiment more certain, it ispreferable that the lower limit value of the conditional expression (10)is 53.00. To make the effect of the fourth embodiment even more certain,it is preferable that the lower limit value of the conditionalexpression (10) is 54.50.

In the fourth embodiment, it is preferable that a condition expressed bythe following expression (11)−0.30<(r5R+r5F)/(r5R−r5F)<0.40  (11)is satisfied, where r5F is a radius of curvature of the object side lenssurface of the second positive lens component L5 of the second lensgroup G2, and r5R is a radius of curvature of the image side lenssurface of the second positive lens component L5 of the second lensgroup G2.

The conditional expression (11) is a conditional expression to correctthe coma aberration and distortion generated in the second positive lenscomponent L5 of the second lens group G2 alone satisfactorily. If theupper limit value of the conditional expression (11) is exceeded, thecoma aberration generated in the second positive lens component L5 ofthe second lens group G2 alone cannot be corrected. Distortion alsoincreases, which is not preferable. If the lower limit value of theconditional expression (11) is not reached, on the other hand, the comaaberration generated in the second positive lens component L5 of thesecond lens group G2 alone increases too much, and performance in theshortest photographic distance deteriorates, which is not preferable.

To make the effect of the fourth embodiment certain, it is preferablethat the upper limit value of the conditional expression (11) is 0.35.To make the effect of the fourth embodiment more certain, it ispreferable that the upper limit value of the conditional expression (11)is 0.30. To make the effect of the fourth embodiment even more certain,it is preferable that the upper limit value of the conditionalexpression (11) is 0.25.

To make the effect of the fourth embodiment certain, it is preferablethat the lower limit value of the conditional expression (11) is −0.25.To make the effect of the fourth embodiment more certain, it ispreferable that the lower limit value of the conditional expression (11)is −0.22. To make the effect of the fourth embodiment even more certain,it is preferable that the lower limit value of the conditionalexpression (11) is −0.19.

In the fourth embodiment, it is preferable that a condition expressed bythe following expression (12)0.60<f/f5<0.90  (12)is satisfied, where f is a focal length of the imaging lens, and f5 is afocal length of the second positive lens component L5 of the second lensgroup G2.

The conditional expression (12) is a conditional expression to specifyan appropriate range of refractive power distribution of the secondpositive lens component L5 of the second lens group G2. If the upperlimit value of the conditional expression (12) is exceeded, therefractive power of the second positive lens component L5 of the secondlens group G2 becomes strong, and the spherical aberration and comaaberration deteriorate. If the lower limit value of the conditionalexpression (12) is not reached, on the other hand, the focal length f5of the second positive lens component L5 increases, and the sphericalaberration is corrected satisfactorily. However, the focal length of thesecond lens group G2 also increases, that is, the total length of thelens increases, and as a result, downsizing of the imaging lens cannotbe implemented. Also the refractive power of the second lens group G2decreases, and if the second lens group G2 is a focusing lens group, themoving distance during focus adjustment increases, which is notpreferable.

To make the effect of the fourth embodiment certain, it is preferablethat the upper limit value of the conditional expression (12) is 0.88.To make the effect of the fourth embodiment more certain, it ispreferable that the upper limit value of the conditional expression (12)is 0.86. To make the effect of the fourth embodiment even more certain,it is preferable that the upper limit value of the conditionalexpression (12) is 0.84.

To make the effect of the fourth embodiment certain, it is preferablethat the lower limit value of the conditional expression (12) is 0.63.To make the effect of the fourth embodiment more certain, it ispreferable that the lower limit value of the conditional expression (12)is 0.66. To make the effect of the fourth embodiment even more certain,it is preferable that the lower limit value of the conditionalexpression (12) is 0.70.

In the fourth embodiment, it is preferable that the first lens group G1further comprises a negative meniscus lens L1 having a convex surfacefacing the object, and a positive meniscus lens L2 having a convexsurface facing the object, which are disposed in order from the object.Because of this configuration, higher performance and downsizing can bebalanced, and the spherical aberration and curvature of field generatedin the first lens group G1 alone can be corrected satisfactorily.

In the fourth embodiment, it is preferable that the second lens group G2further comprises a cemented lens L34 of the negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 having a convex surface facing the image, and a biconvex positivelens L5, which are disposed in order from the object. Because of thisconfiguration, in the imaging lens SL of the fourth embodiment thecurvature of field and coma aberration can be corrected satisfactorily,and higher performance of the imaging lens SL can be implemented.

In the fourth embodiment, it is preferable that the first lens group G1includes at least one aspherical surface (second surface from the objectin FIG. 51). Because of this configuration, higher performance anddownsizing can be balanced, and the spherical aberration and curvatureof field can be corrected satisfactorily.

In the fourth embodiment, it is preferable that the negative lens L1 ofthe first lens group G1 includes at least one aspherical surface (secondsurface from the object in FIG. 51). Because of this configuration,higher performance and downsizing can be balanced, and the sphericalaberration and curvature of field can be corrected satisfactorily.

In the fourth embodiment, it is preferable that the second lens group G2includes at least one aspherical surface (twelfth surface from theobject in FIG. 51). Because of this configuration, fluctuation ofdistortion and curvature of field generated upon focusing can becorrected satisfactorily, and higher performance of the imaging lens SLcan be implemented.

It is also preferable that the second positive lens component L5 of thesecond lens group G2 includes at least one aspherical surface (twelfthsurface from the object in FIG. 51). Because of this configuration,fluctuation of distortion and curvature of field generated upon focusingcan be corrected satisfactorily, and higher performance of the imaginglens SL can be implemented.

In the fourth embodiment, it is preferable that focus on a close objectis adjusted by moving the second lens group G2 toward the object.Because of this configuration, fluctuation of aberration upon focusadjustment can be suppressed, and interference of a lens or a mechanismcomponent to support a lens can be prevented, since the feed pitch ofthe second lens group G2 toward the object upon focus adjustment is verysmall. It is possible to adjust focus on a close object using the firstlens group G1, but the feed pitch toward the object becomes very large,which causes a change in the total length of the lens. Along with thischange, such a mechanism as a drive system becomes complicated, anddownsizing becomes difficult. Also deterioration of the sphericalaberration and curvature of field increase, which is not preferable.

In the fourth embodiment, in order to prevent failure of photography dueto an image blur caused by camera motion, it is possible that a blurdetection system for detecting the blur of the lens system and drivemeans are combined in the lens system, and all or a part of one lensgroup, out of the lens group constituting the lens system, aredecentered as a shift lens group, and an image is shifted by driving theshift lens group by the drive means, so as to correct the image blur(fluctuation of image plane position) caused by a blur of the lenssystem detected by the blur detection system, thereby the image blur canbe corrected. As mentioned above, the imaging lens SL of the fourthembodiment can function as a vibration proof optical system.

The imaging lens SL according to the fourth embodiment comprises twolens groups, that is, the first lens group G1 and the second lens groupG2, but another lens group may be added between the lens groups oranother lens group may be added adjacent to the image side of the firstlens group G1 or the object side of the second lens group G2.

In the imaging lens SL according to the fourth embodiment, it ispreferable that the distance from the image side lens surface to theimage plane (back focus) of the positive lens L5 disposed closest to theimage is about 10 to 30 mm in the shortest state. In the imaging lensSL, it is preferable that the image height is 5 to 12.5 mm, and morepreferably is 5 to 9.5 mm.

Examples of the Fourth Embodiment

Example 4-1 to Example 4-8 according to the fourth embodiment will nowbe described with reference to the drawings. FIG. 51, FIG. 53, FIG. 55,FIG. 57, FIG. 59, FIG. 61, FIG. 63 and FIG. 65 are cross-sectional viewsdepicting a configuration of the imaging lens SL (SL1 to SL8) accordingto each example, where the change of focusing state, from focusing oninfinity to focusing on a close object of the imaging lenses SL1 to SL8,that is, the state of movement of each lens group upon focusing, isshown by an arrow.

As described above, the imaging lens SL1 to SL8 according to eachexample comprises a first lens group G1 having a positive refractivepower, an aperture stop S, a second lens group G2 having a positiverefractive power, and a filter group FL which includes a low passfilter, infrared cut filter or the like, which are disposed in orderfrom an object. Upon focusing from the state of focusing on infinity tothe state of focusing on a close object, the first lens group G1 isfixed with respect to the image plane I, and the second lens group G2 ismoved with respect to the image plane I, so as to change the distancebetween the first lens group G1 and the second lens group G2. The imageplane I is formed on an unillustrated image sensing element, and thisimage sensing element is CCD or CMOS, for example.

Table 4-1 to Table 4-8 shown below are tables of each parameteraccording to Example 4-1 to Example 4-8. Description on the tables,which is the same as the table of the first embodiment, is omitted. In[conditional expression], values corresponding to the conditionalexpressions (9) to (12) are shown.

Example 4-1

The imaging lens SL1 according to Example 4-1 will now be described withreference to FIG. 51, FIGS. 52A and 523 and Table 4-1. As FIG. 51 shows,in the imaging lens SL1 according to Example 4-1, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-1, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-1 shows a table on each parameter of Example 4-1. The surfacenumbers 1 to 18 in Table 4-1 correspond to the surfaces 1 to 18 in FIG.51. In Example 4-1, the second surface and the twelfth surface areaspherical.

TABLE 4-1 [Surface data] Surface number r d nd νd  1 12.5540 0.901.67790 54.89 *2 5.1200 0.80  3 7.2279 1.90 1.88300 40.76  4 25.29520.80  5 0.0000 1.40 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.00 (Flare stop S2)  8 −5.1593 0.90 1.80810 22.76  9 −15.09682.65 1.75500 52.32 10 −6.5278 0.20 11 25.0474 2.70 1.58913 61.16 *12 −19.8008 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.1200 κ = +0.9952 C4 =−3.5496E−04 C6 = −1.3835E−05 C8 = −6.4411E−08 C10 = −2.8213E−08 Twelfthsurface r = −19.8008 κ = +5.2781 C4 = +2.1953E−04 C6 = −1.0580E−07 C8 =+2.9574E−08 C10 = −2.6872E−10 [Various data] f = 14.26 FNO = 2.83 2ω =62.12 Y = 8.50 TL = 31.51 [Variable distance data] Infinity Close Objectd6 1.8514 0.6000 d12 10.4286 11.6800 Bf 0.5058 0.5058 [Lens group data]First surface Focal length First lens group 1 58.2236 Second lens group7 14.9735 [Conditional expression] nd5 = 1.58913 νd5 = 61.16 r5F =25.0474 r5R = −19.8008 f = 14.2560 f5 = 19.1996 Conditional expression(9) nd5 = 1.58913 Conditional expression (10) νd5 = 61.16 Conditionalexpression (11) (r5R + r5F)/(r5R − r5F) = −0.1170 Conditional expression(12) f/f5 = 0.7425

As the parameter table in Table 4-1 shows, the imaging lens SL1according to Example 4-1 satisfies the conditional expressions (9) and(12).

FIGS. 52A and 52B are graphs showing aberrations of the imaging lens SL1according to Example 4-1, where FIG. 52A are graphs showing variousaberrations upon focusing on infinity, and FIG. 52B are graphs showingvarious aberrations upon focusing on a close object. In each graphshowing aberrations, NA is a numerical aperture, FNO is an F number, Ais a half angle of view with respect to each image height, and HO is aheight of an object. d indicates aberrations with respect to the d-line(wavelength: 587.6 nm), g indicates aberrations with respect to theg-line (wavelength: 435.8 nm), C indicates aberrations with respect tothe C-line (wavelength: 656.3 nm), F indicates aberrations with respectto the F-line (wavelength: 486.1 nm), and data with no indication is anaberration with respect to the d-line. In the graph showing astigmatism,a solid line indicates a sagittal image surface, and a broken lineindicates a meridional image surface.

The above description on the graphs showing aberration is the same forother examples, therefore description thereof is omitted.

As each graph showing aberrations shows, in the imaging lens SL1according to Example 4-1, various aberrations are correctedsatisfactorily from the state of focusing on infinity to the state offocusing on a close object, and an excellent image performance isimplemented.

Example 4-2

The imaging lens SL2 according to Example 4-2 will now be described withreference to FIG. 53, FIGS. 54A and 54B and Table 4-2. As FIG. 53 shows,in the imaging lens SL2 according to Example 4-2, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-2, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-2 shows a table on each parameter of Example 4-2. The surfacenumbers 1 to 18 in Table 4-2 correspond to the surfaces 1 to 18 in FIG.53. In Example 4-2, the second surface and the twelfth surface areaspherical.

TABLE 4-2 [Surface data] Surface number r d nd νd  1 11.8261 0.901.67790 54.89 *2 5.0108 0.65  3 7.0263 1.85 1.88300 40.76  4 23.35670.70  5 0.0000 1.40 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.00 (Flare stop S2)  8 −5.0661 0.90 1.80810 22.76  9 −14.63102.70 1.75500 52.32 10 −6.3977 0.20 11 23.5294 2.70 1.58913 61.16 *12 −21.4493 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.0108 κ = +0.1277 C4 =+4.8479E−04 C6 = +5.6078E−06 C8 = +1.1439E−07 C10 = +2.6889E−09 Twelfthsurface r = −21.4493 κ = −5.6807 C4 = +6.6823E−05 C6 = −6.8560E−08 C8 =+2.3185E−08 C10 = −3.6236E−10 [Various data] f = 14.26 FNO = 2.88 2ω =62.12 Y = 8.50 TL = 31.01 [Variable distance data] Infinity Close Objectd6 1.8508 0.6000 d12 10.1792 11.4301 Bf 0.5070 0.5070 [Lens group data]First surface Focal length First lens group 1 56.8827 Second lens group7 14.7636 [Conditional expression] nd5 = 1.58913 νd5 = 61.16 r5F =23.5294 r5R = −21.4493 f = 14.2560 f5 = 19.4796 Conditional expression(9) nd5 = 1.58913 Conditional expression (10) νd5 = 61.16 Conditionalexpression (11) (r5R + r5F)/(r5R − r5F) = −0.0462 Conditional expression(12) f/f5 = 0.7318Table 1-2 shows a table on each parameter of Example 1-2. The surfacenumbers 1 to 18 in Table 1-2 correspond to the surfaces 1 to 18 in FIG.5. In Example 1-2, the second surface and the twelfth surface areaspherical.

As the parameter table in Table 4-2 shows, the imaging lens SL2according to Example 4-2 satisfies the conditional expressions (9) and(12).

FIG. 54A are graphs showing aberrations of the imaging lens SL2according to Example 4-2, where FIG. 54A are graphs showing variousaberrations upon focusing on infinity, and FIG. 54B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL2 according to Example4-2, various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Example 4-3

The imaging lens SL3 according to Example 4-3 will now be described withreference to FIG. 55, FIGS. 56A and 56B and Table 4-3. As FIG. 55 shows,in the imaging lens SL3 according to Example 4-3, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-3, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-3 shows a table on each parameter of Example 4-3. The surfacenumbers 1 to 18 in Table 4-3 correspond to the surfaces 1 to 18 in FIG.55. In Example 4-3, the second surface and the twelfth surface areaspherical.

TABLE 4-3 Surface number r d nd νd  1 12.6464 0.90 1.66910 55.42 *25.7001 0.75  3 7.7231 1.67 1.88300 40.76  4 24.6238 0.20  5 0.0000 1.40(Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  7 0.0000 1.50 (Flarestop S2)  8 −5.0699 0.90 1.80810 22.76  9 −18.5950 3.00 1.80400 46.57 10−7.0355 0.20 11 26.7580 3.12 1.61881 63.85 *12  −18.8179 (d12) 13 0.00001.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.14 16 0.00000.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Aspherical data]Second surface r = 5.7001 κ = +1.7002 C4 = −7.4793E−04 C6 = −3.1424E−05C8 = +2.0843E−07 C10 = −1.3010E−07 Twelfth surface r = −18.8179 κ =−7.0961 C4 = −3.0038E−05 C6 = +1.0404E−06 C8 = −1.2568E−09 C10 =−4.7030E−11 [Various data] f = 14.26 FNO = 2.91 2ω = 62.12 Y = 8.50 TL =32.01 [Variable distance data] Infinity Close Object d6 2.4197 1.1500d12 9.9683 11.2380 Bf 0.5123 0.5123 [Lens group data] First surfaceFocal length First lens group 1 48.8782 Second lens group 7 14.6742[Conditional expression] nd5 = 1.61881 νd5 = 63.85 r5F = 26.7580 r5R =−18.8179 f = 14.2560 f5 = 18.3342 Conditional expression (9) nd5 =1.61881 Conditional expression (10) νd5 = 63.85 Conditional expression(11) (r5R + r5F)/(r5R − r5F) = −0.1742 Conditional expression (12) f/f5= 0.7776

As the parameter table in Table 4-3 shows, the imaging lens SL3according to Example 4-3 satisfies the conditional expressions (9) and(12).

FIGS. 56A and 56B are graphs showing aberrations of the imaging lens SL3according to Example 4-3, where FIG. 56A are graphs showing variousaberrations upon focusing on infinity, and FIG. 56B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL3 according to Example4-3, various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Example 4-4

The imaging lens SL4 according to Example 4-4 will now be described withreference to FIG. 57, FIGS. 58A and 58B and Table 4-4. As FIG. 57 shows,in the imaging lens SL4 according to Example 4-4, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-4, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-4 shows a table on each parameter of Example 4-4. The surfacenumbers 1 to 18 in Table 4-4 correspond to the surfaces 1 to 18 in FIG.57. In Example 4-1, the second surface and the twelfth surface areaspherical.

TABLE 4-4 [Surface data] Surface number r d nd νd  1 9.9874 0.90 1.6889331.08 *2 5.0739 0.45  3 6.3837 1.76 1.85026 32.35  4 17.4312 0.30  50.0000 1.95 (Flare stop S1)  6 0.0000 0.45 (Aperture stop S)  7 0.00001.50 (Flare stop S2)  8 −4.8003 0.90 1.80810 22.76  9 −18.5588 2.981.81600 46.62 10 −6.7015 0.20 11 20.2148 2.86 1.66910 55.42 *12 −30.3443 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 5.0739 κ = −2.9635 C4 =+3.4708E−03 C6 = −1.4779E−04 C8 = +8.3851E−06 C10 = −2.3110E−07 Twelfthsurface r = −30.3443 κ = −0.7304 C4 = +1.2477E−04 C6 = +4.7254E−07 C8 =+9.6784E−09 C10 = −1.1595E−10 [Various data] f = 14.26 FNO = 2.91 2ω =62.12 Y = 8.50 TL = 30.00 [Variable distance data] Infinity Close Objectd6 1.7473 0.4500 d12 8.4731 9.7704 Bf 0.4998 0.4998 [Lens group data]First surface Focal length First lens group 1 38.8259 Second lens group7 14.1972 [Conditional expression] nd5 = 1.66910 νd5 = 55.42 r5F =20.2148 r5R = −30.3443 f = 14.2560 f5 = 18.5540 Conditional expression(9) nd5 = 1.66910 Conditional expression (10) νd5 = 55.42 Conditionalexpression (11) (r5R + r5F)/(r5R − r5F) = 0.2004 Conditional expression(12) f/f5 = 0.7684

As the parameter table in Table 4-4 shows, the imaging lens SL4according to Example 4-4 satisfies the conditional expressions (9) and(12).

FIGS. 58A and 58B are graphs showing aberrations of the imaging lens SL4according to Example 4-4, where FIG. 58A are graphs showing variousaberrations upon focusing on infinity, and FIG. 58B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL4 according to Example4-4, various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Example 4-5

The imaging lens SL5 according to Example 4-5 will now be described withreference to FIG. 59, FIGS. 60A and 60B and Table 4-5. As FIG. 59 shows,in the imaging lens SL5 according to Example 4-5, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-5, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-5 shows a table on each parameter of Example 4-5. The surfacenumbers 1 to 18 in Table 4-5 correspond to the surfaces 1 to 18 in FIG.59. In Example 4-5, the second surface and the twelfth surface areaspherical.

TABLE 4-5 [Surface data] Surface number r d nd νd  1 9.3520 0.90 1.6779054.89 *2 4.8208 0.45  3 5.9177 1.85 1.81600 46.62  4 15.9734 0.35  50.0000 1.95 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  7 0.00001.60 (Flare stop S2)  8 −4.6847 0.90 1.80810 22.76  9 −18.5193 3.041.81600 46.62 10 −6.7523 0.20 11 19.5054 3.10 1.66910 55.42 *12 −28.1863 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 4.8208 κ = −2.2502 C4 =+3.2855E−03 C6 = −1.1017E−04 C8 = +6.2421E−06 C10 = −1.6029E−07 Twelfthsurface r = −28.1863 κ = +3.4908 C4 = +1.4959E−04 C6 = −3.4328E−07 C8 =+5.0300E−09 C10 = −5.9841E−11 [Various data] f = 14.26 FNO = 2.92 2ω =62.12 Y = 8.50 TL = 30.00 [Variable distance data] Infinity Close Objectd6 1.6152 0.3000 d12 8.0762 9.3915 Bf 0.4989 0.4989 [Lens group data]First surface Focal length First lens group 1 36.9620 Second lens group7 14.0056 [Conditional expression] nd5 = 1.66910 νd5 = 55.42 r5F =19.5054 r5R = −28.1863 f = 14.2560 f5 = 17.6895 Conditional expression(9) nd5 = 1.66910 Conditional expression (10) νd5 = 55.42 Conditionalexpression (11) (r5R + r5F)/(r5R − r5F) = 0.1820 Conditional expression(12) f/f5 = 0.8059

As the parameter table in Table 4-5 shows, the imaging lens SL5according to Example 4-5 satisfies the conditional expressions (9) and(12).

FIGS. 60A and 60B are graphs showing aberrations of the imaging lens SL5according to Example 4-5, where FIG. 60A are graphs showing variousaberrations upon focusing on infinity, and FIG. 60B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL5 according to Example4-5 various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Example 4-6

The imaging lens SL6 according to Example 4-6 will now be described withreference to FIG. 61, FIGS. 62A and 62B and Table 4-6. As FIG. 61 shows,in the imaging lens SL6 according to Example 4-6, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-6, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-6 shows a table on each parameter of Example 4-6. The surfacenumbers 1 to 18 in Table 4-6 correspond to the surfaces 1 to 18 in FIG.61. In Example 4-6, the second surface and the twelfth surface areaspherical.

TABLE 4-6 [Surface data] Surface number r d nd νd  1 8.7469 0.90 1.6779054.89 *2 4.6799 0.45  3 5.8268 1.85 1.81600 46.62  4 14.7269 0.35  50.0000 1.95 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  7 0.00001.45 (Flare stop S2)  8 −4.7008 0.90 1.80810 22.76  9 −19.5674 3.051.81600 46.62 10 −6.8100 0.20 11 20.7908 3.10 1.66910 55.42 *12 −24.7647 (d12) 13 0.0000 1.00 1.51633 64.14 14 0.0000 1.50 15 0.00001.87 1.51633 64.14 16 0.0000 0.40 17 0.0000 0.70 1.51633 64.14 18 0.0000(Bf) [Aspherical data] Second surface r = 4.6799 κ = −1.0342 C4 =+2.1291E−03 C6 = −2.5886E−05 C8 = +2.2070E−06 C10 = −5.3593E−08 Twelfthsurface r = −24.7647 κ = −7.3551 C4 = +6.0709E−05 C6 = +1.2096E−08 C8 =+2.7737E−09 C10 = −5.6169E−11 [Various data] f = 14.26 FNO = 2.91 2ω =62.12 Y = 8.50 TL = 30.00 [Variable distance data] Infinity Close Objectd6 1.6575 0.3500 d12 8.1725 9.4800 Bf 0.4953 0.4953 [Lens group data]First surface Focal length First lens group 1 37.8004 Second lens group7 13.8767 [Conditional expression] nd5 = 1.66910 νd5 = 55.42 r5F =20.7908 r5R = −24.7647 f = 14.2560 f5 = 17.3655 Conditional expression(9) nd5 = 1.66910 Conditional expression (10) νd5 = 55.42 Conditionalexpression (11) (r5R + r5F)/(r5R − r5F) = 0.0872 Conditional expression(12) f/f5 = 0.8209

As the parameter table in Table 4-6 shows, the imaging lens SL6according to Example 4-6 satisfies the conditional expressions (9) and(12).

FIGS. 62A and 62B are graphs showing aberrations of the Imaging lens SL6according to Example 4-6, where FIG. 62A are graphs showing variousaberrations upon focusing on infinity, and FIG. 62B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL6 according to Example4-6, various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Example 4-7

The imaging lens SL7 according to Example 4-7 will now be described withreference to FIG. 63, FIGS. 64A and 64B and Table 4-7. As FIG. 63 shows,in the imaging lens SL7 according to Example 4-7, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-7, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-7 shows a table on each parameter of Example 4-7. The surfacenumbers 1 to 18 in Table 4-7 correspond to the surfaces 1 to 18 in FIG.63. In Example 4-7, the second surface and the twelfth surface areaspherical.

TABLE 4-7 Surface number r d nd νd  1 14.0147 0.90 1.67790 54.89 *25.4694 0.90  3 7.6437 1.75 1.88300 40.76  4 30.8895 0.25  5 0.0000 1.60(Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  7 0.0000 1.25 (Flarestop S2)  8 −5.1623 0.95 1.80810 22.76  9 −14.4718 2.75 1.75500 52.32 10−6.7218 0.20 11 26.5149 2.85 1.59201 67.02 *12  −18.8905 (d12) 13 0.00001.00 1.51633 64.14 14 0.0000 1.50 15 0.0000 1.87 1.51633 64.14 16 0.00000.40 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf) [Aspherical data]Second surface r = 5.4694 κ = +1.4173 C4 = −6.4702E−04 C6 = −2.1283E−05C8 = −4.5161E−07 C10 = −6.2922E−08 Twelfth surface r = −18.8905 κ =+5.5850 C4 = +2.2637E−04 C6 = +8.5167E−07 C8 = +1.1963E−08 C10 =+1.5290E−10 [Various data] f = 14.26 FNO = 2.83 2ω = 62.07 Y = 8.50 TL =32.01 [Variable distance data] Infinity Close Object d6 2.0676 0.8000d12 10.5324 11.8300 Bf 0.5145 0.5145 [Lens group data] First surfaceFocal length First lens group 1 51.9495 Second lens group 7 15.2959[Conditional expression] nd5 = 1.59201 νd5 = 67.02 r5F = 26.5149 r5R =−18.8905 f = 14.2560 f5 = 19.0788 Conditional expression (9) nd5 =1.59201 Conditional expression (10) νd5 = 67.02 Conditional expression(11) (r5R + r5F)/(r5R − r5F) = −0.1679 Conditional expression (12) f/f5= 0.7472

As the parameter table in Table 4-7 shows, the imaging lens SL7according to Example 4-7 satisfies the conditional expressions (9) and(12).

FIGS. 64A and 64B are graphs showing aberrations of the imaging lens SL7according to Example 4-7, where FIG. 64A are graphs showing variousaberrations upon focusing on infinity, and FIG. 64B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL7 according to Example4-7, various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Example 4-8

The imaging lens SL8 according to Example 4-8 will now be described withreference to FIG. 65, FIGS. 66A and 66B and Table 4-8. As FIG. 65 shows,in the imaging lens SL8 according to Example 4-8, a first lens group G1comprises a negative meniscus lens L1 having a convex surface facing theobject, and a positive meniscus lens L2 having a convex surface facingthe object, which are dispersed in order from the object. A second lensgroup G2 comprises a cemented lens L34 of a negative meniscus lens L3having a concave surface facing the object and a positive meniscus lensL4 (first positive lens component) having a convex surface facing theimage, and a biconvex positive lens L5 (second positive lens component),which are disposed in order from the object.

An aperture stop S is disposed between the first lens group G1 and thesecond lens group G2, and is fixed with respect to the first lens groupG1 or the image plane I upon focusing from infinity to a close object.Also a flare stop S1 and flare stop S2 are disposed at pre-positions andpost positions of the aperture stop S.

In Example 4-8, an axial air distance d6, between the first lens groupG1 and the second lens group G2, and an axial air distance d12 betweenthe second lens group G2 and the filter group FL change upon focusing.

Table 4-8 shows a table on each parameter of Example 4-8. The surfacenumbers 1 to 18 in Table 4-8 correspond to the surfaces 1 to 18 in FIG.65. In Example 4-8, the second surface and the twelfth surface areaspherical.

TABLE 4-8 [Surface data] Surface number r d nd νd  1 14.0077 1.301.67790 54.89 *2 5.3933 0.60  3 7.5715 1.95 1.88300 40.76  4 28.36630.25  5 0.0000 1.75 (Flare stop S1)  6 0.0000 (d6) (Aperture stop S)  70.0000 1.25 (Flare stop S2)  8 −5.2273 0.98 1.80810 22.76  9 −15.14712.88 1.75500 52.32 10 −6.7013 0.20 11 23.0044 2.94 1.59201 67.02 *12 −20.7345 8.96 13 0.0000 0.50 1.51633 64.14 14 0.0000 4.60 15 0.0000 1.871.51633 64.14 16 0.0000 0.30 17 0.0000 0.70 1.51633 64.14 18 0.0000 (Bf)[Aspherical data] Second surface r = 5.3933 κ = +1.7327 C4 = −9.1467E−04C6 = −4.4123E−05 C8 = +8.7126E−07 C10 = −2.7436E−07 Twelfth surface r =−20.7345 κ = −19.0000 C4 = −1.4487E−04 C6 = +4.4684E−06 C8 = −5.5750E−08C10 = +3.1253E−10 [Various data] f = 14.26 FNO = 2.92 2ω = 62.50 Y =8.50 TL = 32.36 [Variable distance data] Infinity Close Object d6 2.03760.8000 d12 7.7203 8.9579 Bf 0.5348 0.5348 [Lens group data] Firstsurface Focal length First lens group 1 51.9495 Second lens group 714.3554 [Conditional expression] nd5 = 1.59201 νd5 = 67.02 r5F = 23.0044r5R = −20.7345 f = 14.2560 f5 = 18.8933 Conditional expression (9) nd5 =1.59201 Conditional expression (10) νd5 = 67.02 Conditional expression(11) (r5R + r5F)/(r5R − r5F) = −0.0519 Conditional expression (12) f/f5= 0.7546

As the parameter table in Table 4-8 shows, the imaging lens SL8according to Example 4-8 satisfies the conditional expressions (9) and(12).

FIGS. 66A and 66B are graphs showing aberrations of the imaging lens SL8according to Example 4-8, where FIG. 66A are graphs showing variousaberrations upon focusing on infinity, and FIG. 66B are graphs showingvarious aberrations upon focusing on a close object. As each graphshowing aberrations shows, in the imaging lens SL8 according to Example4-8, various aberrations are corrected satisfactorily from the state offocusing on infinity to the state of focusing on a close object, and anexcellent image performance is implemented.

Now a method for manufacturing the imaging lens will be described inbrief with reference to FIG. 67. In this method, the first lens group G1and the second lens group G2 of the present embodiment are assembled ina cylindrical lens barrel (step S1). When each lens group is assembledin the lens barrel, each lens group may be assembled in the lens barrelone at a time according to the sequence along the optical axis, or apart or all of the lens group may be held together using a holdingelement, and assembled. It is preferable that after each lens group isassembled in the lens barrel, it is checked whether an image of theobject is formed in a state of each lens group being assembled in thelens barrel, in other words, it is checked whether each lens group iscentered (step S2).

After the imaging lens is assembled as above, various operations of theimaging lens are checked (step S3). Examples of the various operationschecked here are a focusing operation where a lens group that focuses ona distant object to a close object moves along the optical axisdirection, and a motion blur correction operation where at least a partof the lenses (preferably all or a part of the second lens group G2)move in a direction perpendicular to the optical axis. In the presentembodiment, the second lens group G2 moves toward the object uponfocusing from a distant object to a close object. The sequence ofchecking various operations can be arbitrary.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. An imaging lens, comprising an object side lens group having apositive refractive power and an image side lens group having a positiverefractive power with an air distance from the object side lens group,which are disposed in order from the object, the image side lens groupfurther including a cemented lens of a negative lens component having aconcave surface facing the object and a positive lens component having aconvex surface facing the image, and a biconvex positive lens component,which are disposed in order from the object, and all or a part of theimage side lens group being able to be shifted in a directionsubstantially perpendicular to the optical axis as a shift lens group.2. The imaging lens according to claim 1, wherein a condition expressedby the following expression is satisfied:0.80<f/fS<1.10 where f is a focal length of the imaging lens, and fS isa focal length of the shift lens group.
 3. The imaging lens according toclaim 1, wherein a condition expressed by the following expression issatisfied:0.13<f2/f1<0.47 where f1 is a focal length of the object side lensgroup, and f2 is a focal length of the image side lens group.
 4. Theimaging lens according to claim 1, wherein an aperture stop is disposedbetween the object side lens group and the image side lens group.
 5. Theimaging lens according to claim 1, wherein the focus on a close objectis adjusted by moving the image side lens group toward the object. 6.The imaging lens according to claim 1, wherein the object side lensgroup comprises the first lens component made of a negative meniscuslens having a convex surface facing the object, and the second lenscomponent made of a positive meniscus lens having a convex surfacefacing the object, which are disposed in order from the object.
 7. Theimaging lens according to claim 1, wherein the image side lens groupcomprises a biconvex positive lens, and the biconvex positive lensincludes at least one aspherical surface.
 8. The imaging lens accordingto claim 1, wherein a condition expressed by the following expressionbeing satisfied:3.0<TL/Ymax<4.0 where TL is a total length of the imaging lens, and Ymaxis a maximum image height.
 9. The imaging lens according to claim 1,wherein a condition expressed by of the following expression issatisfied:1.7<TL/Σd<2.2 where TL is a total length of the imaging lens, and Σd isa length on the optical axis, from a lens surface closest to the objectin the object side lens group to a lens surface closest to the image inthe image side lens group.
 10. The imaging lens according to claim 1,wherein the image side lens group comprises a cemented lens of anegative meniscus lens having a concave surface facing the object and apositive meniscus lens having a convex surface facing the image, and abiconvex positive lens, which are disposed in order from the object. 11.The imaging lens according to claim 1, wherein the image side lens groupincludes at least one aspherical surface.
 12. An optical apparatus,comprising an imaging lens that forms an image of an object on apredetermined image surface, wherein the imaging lens is the imaginglens according to claim
 1. 13. The imaging lens according to claim 1,wherein the image side lens group including a cemented lens of anegative lens component and a first positive lens component, and asecond positive lens component, which are disposed in order from theobject, and conditions expressed by the following expressions beingsatisfied:nd5<1.67νd5>50.0 where nd5 is a refractive index of the second positive lenscomponent of the image side lens group on the d-line, and νd5 is an Abbenumber of the second positive lens component of the image side lensgroup on the d-line.
 14. The imaging lens according to claim 13, whereina condition expressed by the following expression is satisfied:−0.30<(r5R+r5F)/(r5R−r5F)<0.40 where r5F is a radius of curvature of anobject side lens surface of the second positive lens component of theimage side lens group, and r5R is a radius of curvature of an image sidelens surface of the second positive lens component of the image sidelens group.
 15. The Imaging lens according to claim 13, wherein acondition represented by the following expression is satisfied:0.60<f/f5<0.90 where f is a focal length of the imaging lens, and f5 isa focal length of the second positive lens component of the image sidelens group.
 16. The imaging lens according to claim 1, wherein theobject side lens group including a first lens component having anegative refractive power and a second lens component having a positiverefractive power, which are disposed in order from the object, andconditions expressed by the following expressions being satisfied:0.12<f/f1<0.470.016<D12/f<0.079 where f1 is a focal length of the object side lensgroup, f is a focal length of an imaging lens, and D12 is an airdistance between the first lens component and the second lens componentof the object side lens group.
 17. The imaging lens according to claim16, wherein a condition expressed by the following expression issatisfied:nd1>1.65 where nd1 is a refractive index of the first lens component ofthe object side lens group on the d-line.
 18. The imaging lens accordingto claim 16, wherein a condition expressed by the following expressionis satisfied:3.8<(r2F+r1R)/(r2F−r1R)<11.8 where r1R is a radius of curvature of animage side lens surface of the first lens component, and r2F is a radiusof curvature of an object side lens surface of the second lenscomponent.
 19. The imaging lens according to claim 16, wherein thenegative lens component of the object side lens group includes at leastone aspherical surface.
 20. A method for manufacturing an imaging lens,comprising the steps of: assembling an object side lens group having apositive refractive power and an image side lens group having a positiverefractive power with an air distance from the object side lens group ina lens barrel in order from the object side; configuring the image sidelens group by disposing a cemented lens of a negative lens componenthaving a concave surface facing the object and a positive lens componenthaving a convex surface facing the image, and a biconvex positive lenscomponent in order from the object when the step of assembling isperformed; and assembling all or a part of the image side lens group asa shift lens group to be shifted in a direction substantiallyperpendicular to the optical.
 21. The method for manufacturing theimaging lens according to claim 20, wherein a condition expressed by thefollowing expression is satisfied:0.80<f/fS<1.10 where f is a focal length of the imaging lens, and fS isa focal length of the shift lens group.
 22. The method for manufacturingthe imaging lens according to claim 20, wherein a condition expressed bythe following expression is satisfied:0.13<f2/f1<0.47 where f1 is a focal length of the object side lensgroup, and f2 is a focal length of the image side lens group.
 23. Themethod for manufacturing the imaging lens according to claim 20, whereinan aperture stop is disposed between the object side lens group and theimage side lens group.
 24. The method for manufacturing the imaging lensaccording to claim 20, wherein the focus on a close object is adjustedby moving the image side lens group toward the object.
 25. The methodfor manufacturing the imaging lens according to claim 20, wherein theobject side lens group comprises the first lens component made of anegative meniscus lens having a convex surface facing the object, andthe second lens component made of a positive meniscus lens having aconvex surface facing the object, which are disposed in order from theobject.
 26. The method for manufacturing the imaging lens according toclaim 20, wherein the image side lens group comprises a biconvexpositive lens, wherein the biconvex positive lens includes at least oneaspherical surface.
 27. The method for manufacturing the imaging lensaccording to claim 20, wherein a condition expressed by the followingexpression being satisfied:3.0<TL/Ymax<4.0 where TL is a total length of the imaging lens, and Ymaxis a maximum image height.
 28. The method for manufacturing the imaginglens according to claim 20, wherein a condition expressed by thefollowing expression is satisfied:1.7<TL/Σd<2.2 where TL is a total length of the imaging lens, and Σd isa length on the optical axis, from a lens surface closest to the objectin the object side lens group to a lens surface closest to the image inthe image side lens group.
 29. The method for manufacturing the imaginglens according to claim 20, wherein the image side lens group comprisesa cemented lens of a negative meniscus lens having a concave surfacefacing the object and a positive meniscus lens having a convex surfacefacing the image, and a biconvex positive lens, which are disposed inorder from the object.
 30. The method for manufacturing the imaging lensaccording to claim 20, wherein the image side lens group includes atleast one aspherical surface.
 31. The method for manufacturing animaging lens according to claim 20, wherein configuring the image sidelens group by disposing a cemented lens of a negative lens component anda first positive lens component, and a second positive lens component inorder from the object when the step of assembling is performed,conditions expressed by the following expressions being satisfied:nd5<1.67νd5>50.0 where nd5 is a refractive index of the second positive lenscomponent of the image side lens group on the d-line, and νd5 is an Abbenumber of the second positive lens of the image side lens group on tothe d-line.
 32. The method for manufacturing the imaging lens accordingto claim 31, wherein a condition expressed by the following expressionis satisfied:−0.30<(r5R+r5F)/(r5R−r5F)<0.40 where r5F is a radius of curvature of anobject side lens surface of the second positive lens component of theimage side lens group, and r5R is a radius of curvature of an image sidelens surface of the second positive lens component of the image sidelens group.
 33. The method for manufacturing the imaging lens accordingto claim 31, wherein a condition expressed by the following expressionis satisfied:0.60<f/f5<0.90 where f is a focal length of the imaging lens, and f5 isa focal length of the second positive lens component of the image sidelens group.
 34. The method for manufacturing the imaging lens accordingto claim 20, wherein configuring the object side lens group by disposinga first lens component having a negative refractive power and a secondlens component having a positive refractive power in order from theobject when the step of assembling is performed, conditions expressed bythe following expressions being satisfied:0.12<f/f1<0.470.016<D12/f<0.079 where f1 is a focal length of the object side lensgroup, f is a focal length of an imaging lens, and D12 is an airdistance between the first lens component and the second lens componentof the object side lens group.
 35. The method for manufacturing theimaging lens according to claim 34, wherein a condition expressed by thefollowing expression is satisfied:nd1>1.65 where nd1 is a refractive index of the first lens component ofthe object side lens group on the d-line.
 36. The method formanufacturing the imaging lens according to claim 34, wherein acondition expressed by the following expression is satisfied:3.8<(r2F+r1R)/(r2F−r1R)<11.8 where r1R is a radius of curvature of animage side lens surface of the first lens component, and r2F is a radiusof curvature of an object side lens surface of the second lenscomponent.
 37. The method for manufacturing the imaging lens accordingto claim 34, wherein the negative lens component of the object side lensgroup includes at least one aspherical surface.